Tools

Suggest an explanation, other than product being lost from the crucible or reacting with nitrogen, that could explain the yield found in (b)(iii).

Suggest an experiment that shows that magnesium is more reactive than zinc, giving the observation that would confirm this.

Describe how the relative reactivity of rhenium, compared to silver, zinc, and copper, can be established using pieces of rhenium and solutions of these metal sulfates.

Describe a test and the expected result to indicate the presence of carbon–carbon double bonds.

Suggest why many chemicals, including hydrogen peroxide, are kept in brown bottles instead of clear colourless bottles.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of
formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

What is the enthalpy of combustion, ΔH_c, of ethanol in kJ mol⁻¹?
Maximum temperature of water: 30.0°C
Initial temperature of water: 20.0°C
Mass of water in beaker: 100.0 g
Loss in mass of ethanol: 0.230 g
M_r (ethanol): 46.08
Specific heat capacity of water: 4.18 J g⁻¹ K⁻¹
q = mcΔT

A.  $-\frac{100.0\times 4.18\times (10.0\times 273)}{{\displaystyle \frac{0.230}{46.08}}\times 1000}$

B.  $-\frac{0.0230\times 4.18\times 10.0}{{\displaystyle \frac{100.0}{46.08}}\times 1000}$

C.  $-\frac{100.0\times 4.18\times 10.0}{{\displaystyle \frac{0.230}{46.08}}\times 1000}$

D.  $-\frac{100.0\times 4.18\times 10.0}{{\displaystyle \frac{0.230}{46.08}}}$

Describe how the relative reactivity of rhenium, compared to silver, zinc, and copper, can be established using pieces of rhenium and solutions of these metal sulfates.

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

Suggest why many chemicals, including hydrogen peroxide, are kept in brown bottles instead of clear colourless bottles.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Calculate the energy released, in kJ g⁻¹, when 3.49 g of starch are completely combusted in a calorimeter, increasing the temperature of 975 g of water from 21.0 °C to 36.0 °C. Use section 1 of the data booklet.

Determine from the graph the rate of reaction at 20 s, in cm³ s⁻¹, showing your working.

Outline, with a reason, another property that could be monitored to measure the rate of this reaction.

Calculate the energy released, in kJ g⁻¹, when 3.49 g of starch are completely combusted in a calorimeter, increasing the temperature of 975 g of water from 21.0 °C to 36.0 °C. Use section 1 of the data booklet.

Determine from the graph the rate of reaction at 20 s, in cm³ s⁻¹, showing your working.

Outline, with a reason, another property that could be monitored to measure the rate of this reaction.

The dotted line represents the formation of oxygen, O₂(g), from the uncatalysed complete decomposition of hydrogen peroxide, H₂O₂ (aq).

Which curve represents a catalysed reaction under the same conditions?

Another airbag reactant produces nitrogen gas and sodium.

Suggest, including an equation, why the products of this reactant present a safety hazard.

Determine the initial rate of reaction of limestone with nitric acid from the graph.

Show your working on the graph and include the units of the initial rate.

Explain why the rate of reaction of limestone with nitric acid decreases and reaches zero over the period of five days.

What is the pH of 0.001 mol dm⁻³ NaOH (aq)?

A. 1

B. 3

C. 11

D. 13

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

Identify the independent and dependent variables in this experiment.

An additional experiment was conducted in which only the sulfuric acid catalyst was titrated with $\mathrm{NaOH}\hspace{0.17em}\left(\mathrm{aq}\right)$. Outline why this experiment was necessary.

Comment on the magnitudes of random and systematic errors in this experiment using the answers in (e).

The energy from burning 0.250 g of ethanol causes the temperature of 150 cm³ of water to rise by 10.5 °C. What is the enthalpy of combustion of ethanol, in kJ mol^–1?

Specific heat capacity of water: 4.18 J g^–1K^–1.

A.  $\frac{150\times 4.18\times 10.5}{{\displaystyle \frac{0.250}{46.08}}}$

B.  $\frac{150\times 4.18\times 10.5}{{\displaystyle \frac{0.250}{46.08}}\times 1000}$

C.  $\frac{150\times 4.18\times \left(273+10.5\right)}{{\displaystyle \frac{0.250}{46.08}}}$

D.  $\frac{150\times 4.18\times \left(273+10.5\right)}{{\displaystyle \frac{0.250}{46.08}}\times 1000}$

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Proteins are polymers of amino acids.

A paper chromatogram of two amino acids, A1 and A2, is obtained using a non-polar solvent.

© International Baccalaureate Organization 2020.

Determine the ${\mathrm{R}}_{\mathrm{f}}$ value of A1.

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Iron has a relatively small specific heat capacity; the temperature of a 50 g sample rises by 44.4°C when it absorbs 1 kJ of heat energy.

Determine the specific heat capacity of iron, in J g⁻¹K⁻¹. Use section 1 of the data booklet.

Which apparatus can be used to monitor the rate of this reaction?

${\mathrm{CH}}_3{\mathrm{COCH}}_3 \left(\mathrm{aq}\right)+{\mathrm{I}}_2 \left(\mathrm{aq}\right)\to {\mathrm{CH}}_3{\mathrm{COCH}}_2\mathrm{I} \left(\mathrm{aq}\right)+{\mathrm{H}}^{+} \left(\mathrm{aq}\right)+{\mathrm{I}}^{-} \left(\mathrm{aq}\right)$

1. A pH meter
2. A gas syringe
3. A colorimeter
   

A.  I and II only

B.  I and III only

C.  II and III only

D.  I, II and III

Suggest why a non-polar solvent was needed.

Proteins are polymers of amino acids. A paper chromatogram of two amino acids, A1 and A2, is obtained using a non-polar solvent.

© International Baccalaureate Organization 2020.

Determine the ${\mathrm{R}}_{\mathrm{f}}$ value of A1.

The vapour pressure of pure ethanal at $20°\mathrm{C}$ is $101 \mathrm{kPa}$.

Calculate the vapour pressure of ethanal above the liquid mixture at $20°\mathrm{C}$.

A student was investigating rates of reaction. In which of the following cases would a colorimeter show a change in absorbance?

A.  KBr (aq) + Cl₂(aq)

B.  Cu (s) + Na₂SO₄(aq)

C.  HCl (aq) + NaOH (aq)

D.  (CH₃)₃COH (aq) + K₂Cr₂O₇(aq)

The rate equation for a reaction is:

rate = k[A][B]

Which mechanism is consistent with this rate equation?

A.  2A $\rightleftharpoons$ I       Fast
     I + B → P    Slow

B.  A + B $\rightleftharpoons$ I   Fast
     I + A → P    Slow

C.  A → I          Slow
     I + B → P    Fast

D.  B $\rightleftharpoons$ I         Fast
     I + A → P    Slow

Determine the molar enthalpy of combustion of an alkane if 8.75 × 10⁻⁴ moles are burned, raising the temperature of 20.0 g of water by 57.3 °C.

Which instrument would best monitor the rate of this reaction?

2KI (aq) + Cl₂(aq) → 2KCl (aq) + I₂(aq)

A.  Balance

B.  Colorimeter

C.  Volumetric flask

D.  Gas syringe

Calculate the volumes of pure ascorbic acid solution required for each point of the calibration curve; point 4 of the curve is shown as an example.

Calculate the volumes of pure ascorbic acid solution required for each point of the calibration curve; point 4 of the curve is shown as an example.

Suggest an explanation, other than product being lost from the crucible or reacting with nitrogen, that could explain the yield found in (b)(iii).

Suggest an explanation, other than product being lost from the crucible or reacting with nitrogen, that could explain the yield found in (b)(iii).

Suggest an experiment that shows that magnesium is more reactive than zinc, giving the observation that would confirm this.

Suggest an experiment that shows that magnesium is more reactive than zinc, giving the observation that would confirm this.

Describe how the relative reactivity of rhenium, compared to silver, zinc, and copper, can be established using pieces of rhenium and solutions of these metal sulfates.

Describe how the relative reactivity of rhenium, compared to silver, zinc, and copper, can be established using pieces of rhenium and solutions of these metal sulfates.

Describe a test and the expected result to indicate the presence of carbon–carbon double bonds.

Describe a test and the expected result to indicate the presence of carbon–carbon double bonds.

Suggest why many chemicals, including hydrogen peroxide, are kept in brown bottles instead of clear colourless bottles.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of
formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Suggest why many chemicals, including hydrogen peroxide, are kept in brown bottles instead of clear colourless bottles.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of
formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

What is the enthalpy of combustion, ΔH_c, of ethanol in kJ mol⁻¹?
Maximum temperature of water: 30.0°C
Initial temperature of water: 20.0°C
Mass of water in beaker: 100.0 g
Loss in mass of ethanol: 0.230 g
M_r (ethanol): 46.08
Specific heat capacity of water: 4.18 J g⁻¹ K⁻¹
q = mcΔT

A.  $-\frac{100.0\times 4.18\times (10.0\times 273)}{{\displaystyle \frac{0.230}{46.08}}\times 1000}$

B.  $-\frac{0.0230\times 4.18\times 10.0}{{\displaystyle \frac{100.0}{46.08}}\times 1000}$

C.  $-\frac{100.0\times 4.18\times 10.0}{{\displaystyle \frac{0.230}{46.08}}\times 1000}$

D.  $-\frac{100.0\times 4.18\times 10.0}{{\displaystyle \frac{0.230}{46.08}}}$

Describe how the relative reactivity of rhenium, compared to silver, zinc, and copper, can be established using pieces of rhenium and solutions of these metal sulfates.

Describe how the relative reactivity of rhenium, compared to silver, zinc, and copper, can be established using pieces of rhenium and solutions of these metal sulfates.

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

Suggest why many chemicals, including hydrogen peroxide, are kept in brown bottles instead of clear colourless bottles.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Suggest why many chemicals, including hydrogen peroxide, are kept in brown bottles instead of clear colourless bottles.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Calculate the energy released, in kJ g⁻¹, when 3.49 g of starch are completely combusted in a calorimeter, increasing the temperature of 975 g of water from 21.0 °C to 36.0 °C. Use section 1 of the data booklet.

Determine from the graph the rate of reaction at 20 s, in cm³ s⁻¹, showing your working.

Outline, with a reason, another property that could be monitored to measure the rate of this reaction.

Calculate the energy released, in kJ g⁻¹, when 3.49 g of starch are completely combusted in a calorimeter, increasing the temperature of 975 g of water from 21.0 °C to 36.0 °C. Use section 1 of the data booklet.

Determine from the graph the rate of reaction at 20 s, in cm³ s⁻¹, showing your working.

Outline, with a reason, another property that could be monitored to measure the rate of this reaction.

The dotted line represents the formation of oxygen, O₂(g), from the uncatalysed complete decomposition of hydrogen peroxide, H₂O₂ (aq).

Which curve represents a catalysed reaction under the same conditions?

Another airbag reactant produces nitrogen gas and sodium.

Suggest, including an equation, why the products of this reactant present a safety hazard.

Another airbag reactant produces nitrogen gas and sodium.

Suggest, including an equation, why the products of this reactant present a safety hazard.

Determine the initial rate of reaction of limestone with nitric acid from the graph.

Show your working on the graph and include the units of the initial rate.

Explain why the rate of reaction of limestone with nitric acid decreases and reaches zero over the period of five days.

What is the pH of 0.001 mol dm⁻³ NaOH (aq)?

A. 1

B. 3

C. 11

D. 13

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

Identify the independent and dependent variables in this experiment.

An additional experiment was conducted in which only the sulfuric acid catalyst was titrated with $\mathrm{NaOH}\hspace{0.17em}\left(\mathrm{aq}\right)$. Outline why this experiment was necessary.

Comment on the magnitudes of random and systematic errors in this experiment using the answers in (e).

The energy from burning 0.250 g of ethanol causes the temperature of 150 cm³ of water to rise by 10.5 °C. What is the enthalpy of combustion of ethanol, in kJ mol^–1?

Specific heat capacity of water: 4.18 J g^–1K^–1.

A.  $\frac{150\times 4.18\times 10.5}{{\displaystyle \frac{0.250}{46.08}}}$

B.  $\frac{150\times 4.18\times 10.5}{{\displaystyle \frac{0.250}{46.08}}\times 1000}$

C.  $\frac{150\times 4.18\times \left(273+10.5\right)}{{\displaystyle \frac{0.250}{46.08}}}$

D.  $\frac{150\times 4.18\times \left(273+10.5\right)}{{\displaystyle \frac{0.250}{46.08}}\times 1000}$

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Proteins are polymers of amino acids.

A paper chromatogram of two amino acids, A1 and A2, is obtained using a non-polar solvent.

© International Baccalaureate Organization 2020.

Determine the ${\mathrm{R}}_{\mathrm{f}}$ value of A1.

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Iron has a relatively small specific heat capacity; the temperature of a 50 g sample rises by 44.4°C when it absorbs 1 kJ of heat energy.

Determine the specific heat capacity of iron, in J g⁻¹K⁻¹. Use section 1 of the data booklet.

Iron has a relatively small specific heat capacity; the temperature of a 50 g sample rises by 44.4°C when it absorbs 1 kJ of heat energy.

Determine the specific heat capacity of iron, in J g⁻¹K⁻¹. Use section 1 of the data booklet.

Which apparatus can be used to monitor the rate of this reaction?

${\mathrm{CH}}_3{\mathrm{COCH}}_3 \left(\mathrm{aq}\right)+{\mathrm{I}}_2 \left(\mathrm{aq}\right)\to {\mathrm{CH}}_3{\mathrm{COCH}}_2\mathrm{I} \left(\mathrm{aq}\right)+{\mathrm{H}}^{+} \left(\mathrm{aq}\right)+{\mathrm{I}}^{-} \left(\mathrm{aq}\right)$

1. A pH meter
2. A gas syringe
3. A colorimeter
   

A.  I and II only

B.  I and III only

C.  II and III only

D.  I, II and III

Suggest why a non-polar solvent was needed.

Proteins are polymers of amino acids. A paper chromatogram of two amino acids, A1 and A2, is obtained using a non-polar solvent.

© International Baccalaureate Organization 2020.

Determine the ${\mathrm{R}}_{\mathrm{f}}$ value of A1.

The vapour pressure of pure ethanal at $20°\mathrm{C}$ is $101 \mathrm{kPa}$.

Calculate the vapour pressure of ethanal above the liquid mixture at $20°\mathrm{C}$.

A student was investigating rates of reaction. In which of the following cases would a colorimeter show a change in absorbance?

A.  KBr (aq) + Cl₂(aq)

B.  Cu (s) + Na₂SO₄(aq)

C.  HCl (aq) + NaOH (aq)

D.  (CH₃)₃COH (aq) + K₂Cr₂O₇(aq)

The rate equation for a reaction is:

rate = k[A][B]

Which mechanism is consistent with this rate equation?

A.  2A $\rightleftharpoons$ I       Fast
     I + B → P    Slow

B.  A + B $\rightleftharpoons$ I   Fast
     I + A → P    Slow

C.  A → I          Slow
     I + B → P    Fast

D.  B $\rightleftharpoons$ I         Fast
     I + A → P    Slow

Determine the molar enthalpy of combustion of an alkane if 8.75 × 10⁻⁴ moles are burned, raising the temperature of 20.0 g of water by 57.3 °C.

Determine the molar enthalpy of combustion of an alkane if 8.75 × 10⁻⁴ moles are burned, raising the temperature of 20.0 g of water by 57.3 °C.

Which instrument would best monitor the rate of this reaction?

2KI (aq) + Cl₂(aq) → 2KCl (aq) + I₂(aq)

A.  Balance

B.  Colorimeter

C.  Volumetric flask

D.  Gas syringe

Calculate the volumes of pure ascorbic acid solution required for each point of the calibration curve; point 4 of the curve is shown as an example.

Calculate the volumes of pure ascorbic acid solution required for each point of the calibration curve; point 4 of the curve is shown as an example.

Calculate the volumes of pure ascorbic acid solution required for each point of the calibration curve; point 4 of the curve is shown as an example.

Calculate the volumes of pure ascorbic acid solution required for each point of the calibration curve; point 4 of the curve is shown as an example.

The experiment gave an error in the rate because the pressure gauge was inaccurate.

Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

The uncertainty of the 100.0cm³ volumetric flask used to make the solution was ±0.6cm³.

Calculate the maximum percentage uncertainty in the mass of NaHCO₃ so that the concentration of the solution is correct to ±1.0 %.

Describe one systematic error associated with the use of the gas syringe, and how the error affects the calculated rate.

Identify one error associated with the use of an accurate stopwatch.

The experiment gave an error in the rate because the pressure gauge was inaccurate. Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

Estimate the time at which the powdered zinc was placed in the beaker.

State what point Y on the graph represents.

The maximum temperature used to calculate the enthalpy of reaction was chosen at a point on the extrapolated (dotted) line.

State the maximum temperature which should be used and outline one assumption made in choosing this temperature on the extrapolated line.

Maximum temperature:

Assumption:

To determine the enthalpy of reaction the experiment was carried out five times. The same volume and concentration of copper(II) sulfate was used but the mass of zinc was different each time. Suggest, with a reason, if zinc or copper(II) sulfate should be in excess for each trial.

The formula q = mcΔT was used to calculate the energy released. The values used in the calculation were m = 25.00 g, c = 4.18 J g⁻¹ K⁻¹.

State an assumption made when using these values for m and c.

Predict, giving a reason, how the final enthalpy of reaction calculated from this experiment would compare with the theoretical value.

Describe one systematic error associated with the use of the gas syringe, and how the error affects the calculated rate.

Identify one error associated with the use of an accurate stopwatch.

Data collected from a larger number of silicon samples could also be plotted to determine the density using the following axes.

Which statements are correct?

    I. The density is the slope of the graph.
    II. The data will show that mass is proportional to volume.
    III. The best-fit line should pass through the origin.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

What is the order of increasing boiling point?

A. CH₃CH₂CH₂CH₃ < CH₃CH(OH)CH₃ < CH₃COCH₃ < CH₃CO₂H

B. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CO₂H

C. CH₃CO₂H < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CH₂CH₂CH₃

D. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CO₂H < CH₃CH(OH)CH₃

Estimate the time at which the powdered zinc was placed in the beaker.

State what point Y on the graph represents.

The maximum temperature used to calculate the enthalpy of reaction was chosen at a point on the extrapolated (dotted) line.

State the maximum temperature which should be used and outline one assumption made in choosing this temperature on the extrapolated line.

Maximum temperature:

Assumption:

To determine the enthalpy of reaction the experiment was carried out five times. The same volume and concentration of copper(II) sulfate was used but the mass of zinc was different each time. Suggest, with a reason, if zinc or copper(II) sulfate should be in excess for each trial.

The formula q = mcΔT was used to calculate the energy released. The values used in the calculation were m = 25.00 g, c = 4.18 J g⁻¹ K⁻¹.

State an assumption made when using these values for m and c.

Predict, giving a reason, how the final enthalpy of reaction calculated from this experiment would compare with the theoretical value.

What is the pH of 0.001 mol dm⁻³ NaOH (aq)?

A. 1

B. 3

C. 11

D. 13

What is the order of increasing boiling point?

A. CH₃CH₂CH₂CH₃ < CH₃CH(OH)CH₃ < CH₃COCH₃ < CH₃CO₂H

B. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CO₂H

C. CH₃CO₂H < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CH₂CH₂CH₃

D. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CO₂H < CH₃CH(OH)CH₃

The experiment gave an error in the rate because the pressure gauge was inaccurate.

Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

The experiment gave an error in the rate because the pressure gauge was inaccurate.

Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

The uncertainty of the 100.0cm³ volumetric flask used to make the solution was ±0.6cm³.

Calculate the maximum percentage uncertainty in the mass of NaHCO₃ so that the concentration of the solution is correct to ±1.0 %.

The uncertainty of the 100.0cm³ volumetric flask used to make the solution was ±0.6cm³.

Calculate the maximum percentage uncertainty in the mass of NaHCO₃ so that the concentration of the solution is correct to ±1.0 %.

Describe one systematic error associated with the use of the gas syringe, and how the error affects the calculated rate.

Identify one error associated with the use of an accurate stopwatch.

The experiment gave an error in the rate because the pressure gauge was inaccurate. Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

The experiment gave an error in the rate because the pressure gauge was inaccurate. Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

Estimate the time at which the powdered zinc was placed in the beaker.

State what point Y on the graph represents.

The maximum temperature used to calculate the enthalpy of reaction was chosen at a point on the extrapolated (dotted) line.

State the maximum temperature which should be used and outline one assumption made in choosing this temperature on the extrapolated line.

Maximum temperature:

Assumption:

To determine the enthalpy of reaction the experiment was carried out five times. The same volume and concentration of copper(II) sulfate was used but the mass of zinc was different each time. Suggest, with a reason, if zinc or copper(II) sulfate should be in excess for each trial.

The formula q = mcΔT was used to calculate the energy released. The values used in the calculation were m = 25.00 g, c = 4.18 J g⁻¹ K⁻¹.

State an assumption made when using these values for m and c.

Predict, giving a reason, how the final enthalpy of reaction calculated from this experiment would compare with the theoretical value.

Describe one systematic error associated with the use of the gas syringe, and how the error affects the calculated rate.

Identify one error associated with the use of an accurate stopwatch.

Data collected from a larger number of silicon samples could also be plotted to determine the density using the following axes.

Which statements are correct?

    I. The density is the slope of the graph.
    II. The data will show that mass is proportional to volume.
    III. The best-fit line should pass through the origin.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

What is the order of increasing boiling point?

A. CH₃CH₂CH₂CH₃ < CH₃CH(OH)CH₃ < CH₃COCH₃ < CH₃CO₂H

B. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CO₂H

C. CH₃CO₂H < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CH₂CH₂CH₃

D. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CO₂H < CH₃CH(OH)CH₃

Estimate the time at which the powdered zinc was placed in the beaker.

State what point Y on the graph represents.

The maximum temperature used to calculate the enthalpy of reaction was chosen at a point on the extrapolated (dotted) line.

State the maximum temperature which should be used and outline one assumption made in choosing this temperature on the extrapolated line.

Maximum temperature:

Assumption:

To determine the enthalpy of reaction the experiment was carried out five times. The same volume and concentration of copper(II) sulfate was used but the mass of zinc was different each time. Suggest, with a reason, if zinc or copper(II) sulfate should be in excess for each trial.

The formula q = mcΔT was used to calculate the energy released. The values used in the calculation were m = 25.00 g, c = 4.18 J g⁻¹ K⁻¹.

State an assumption made when using these values for m and c.

Predict, giving a reason, how the final enthalpy of reaction calculated from this experiment would compare with the theoretical value.

What is the pH of 0.001 mol dm⁻³ NaOH (aq)?

A. 1

B. 3

C. 11

D. 13

What is the order of increasing boiling point?

A. CH₃CH₂CH₂CH₃ < CH₃CH(OH)CH₃ < CH₃COCH₃ < CH₃CO₂H

B. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CO₂H

C. CH₃CO₂H < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CH₂CH₂CH₃

D. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CO₂H < CH₃CH(OH)CH₃

A student performed an experiment to find the melting point of sulfur, obtaining 118.0 °C. The literature value is 115.2 °C. What was the percentage error?

A.  $\frac{118.0-115.2}{115.2}\times 100\%$

B.  $\frac{115.2}{118.0}\times 100\%$

C.  $\frac{118.0-115.2}{118.0}\times 100\%$

D.  $\frac{118.0}{115.2}\times 100\%$

Determine the percentage uncertainty of the mass of product after heating.

Suggest an explanation, other than product being lost from the crucible or reacting with nitrogen, that could explain the yield found in (b)(iii).

20 cm³ of 1 mol dm⁻³ sulfuric acid was added dropwise to 20 cm³ of 1 mol dm⁻³ barium hydroxide producing a precipitate of barium sulfate.

H₂SO₄(aq) + Ba(OH)₂(aq) → 2H₂O (l) + BaSO₄(s)

Which graph represents a plot of conductivity against volume of acid added?

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of
formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

The experiment gave an error in the rate because the pressure gauge was inaccurate.

Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

The dotted line represents the formation of oxygen, O₂ (g), from the uncatalysed complete decomposition of hydrogen peroxide, H₂O₂ (aq).

Which curve represents a catalysed reaction under the same conditions?

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

The uncertainty of the 100.0cm³ volumetric flask used to make the solution was ±0.6cm³.

Calculate the maximum percentage uncertainty in the mass of NaHCO₃ so that the concentration of the solution is correct to ±1.0 %.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Determine from the graph the rate of reaction at 20 s, in cm³ s⁻¹, showing your working.

Describe one systematic error associated with the use of the gas syringe, and how the error affects the calculated rate.

Identify one error associated with the use of an accurate stopwatch.

The experiment gave an error in the rate because the pressure gauge was inaccurate. Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

Estimate the time at which the powdered zinc was placed in the beaker.

State what point Y on the graph represents.

The maximum temperature used to calculate the enthalpy of reaction was chosen at a point on the extrapolated (dotted) line.

State the maximum temperature which should be used and outline one assumption made in choosing this temperature on the extrapolated line.

Maximum temperature:

Assumption:

To determine the enthalpy of reaction the experiment was carried out five times. The same volume and concentration of copper(II) sulfate was used but the mass of zinc was different each time. Suggest, with a reason, if zinc or copper(II) sulfate should be in excess for each trial.

Predict, giving a reason, how the final enthalpy of reaction calculated from this experiment would compare with the theoretical value.

Determine from the graph the rate of reaction at 20 s, in cm³ s⁻¹, showing your working.

Describe one systematic error associated with the use of the gas syringe, and how the error affects the calculated rate.

Identify one error associated with the use of an accurate stopwatch.

The dotted line represents the formation of oxygen, O₂(g), from the uncatalysed complete decomposition of hydrogen peroxide, H₂O₂ (aq).

Which curve represents a catalysed reaction under the same conditions?

Data collected from a larger number of silicon samples could also be plotted to determine the density using the following axes.

Which statements are correct?

    I. The density is the slope of the graph.
    II. The data will show that mass is proportional to volume.
    III. The best-fit line should pass through the origin.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Estimate the time at which the powdered zinc was placed in the beaker.

State what point Y on the graph represents.

The maximum temperature used to calculate the enthalpy of reaction was chosen at a point on the extrapolated (dotted) line.

State the maximum temperature which should be used and outline one assumption made in choosing this temperature on the extrapolated line.

Maximum temperature:

Assumption:

To determine the enthalpy of reaction the experiment was carried out five times. The same volume and concentration of copper(II) sulfate was used but the mass of zinc was different each time. Suggest, with a reason, if zinc or copper(II) sulfate should be in excess for each trial.

Predict, giving a reason, how the final enthalpy of reaction calculated from this experiment would compare with the theoretical value.

Which graph would not show a linear relationship for a fixed mass of an ideal gas with all other variables constant?

A. P against V

B. P against $\frac{1}{\text{V}}$

C. P against T

D. V against T

Calculate the percentage uncertainty of the day 5 titre.

Determine the initial rate of reaction of limestone with nitric acid from the graph.

Show your working on the graph and include the units of the initial rate.

Explain why the rate of reaction of limestone with nitric acid decreases and reaches zero over the period of five days.

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

K_c for 2N₂O (g) $\rightleftharpoons$ 2N₂ (g) + O₂ (g) is 7.3 × 10³⁴.

What is K_c for the following reaction, at the same temperature?

N₂ (g) + $\frac{1}{2}$O₂ (g) $\rightleftharpoons$ N₂O (g)

A. 7.3 × 10³⁴

B. $\frac{1}{\sqrt{7.3\times {10}^{34}}}$

C. $\frac{2}{7.3\times {10}^{34}}$

D. $\frac{1}{2\times 7.3\times {10}^{34}}$

Determine the density of calcium, in g cm⁻³, using section 2 of the data booklet.

Ar = 40.08; metallic radius (r) = 1.97 × 10⁻¹⁰ m

Calculate the percentage uncertainty and percentage error in the experimentally determined value of $K_{\mathrm{c}}$ for methanol.

Comment on the magnitudes of random and systematic errors in this experiment using the answers in (e).

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Proteins are polymers of amino acids.

A paper chromatogram of two amino acids, A1 and A2, is obtained using a non-polar solvent.

© International Baccalaureate Organization 2020.

Determine the ${\mathrm{R}}_{\mathrm{f}}$ value of A1.

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Which graph represents the relationship between the rate constant, $k$, and temperature, $T$, in kelvin?

Proteins are polymers of amino acids. A paper chromatogram of two amino acids, A1 and A2, is obtained using a non-polar solvent.

© International Baccalaureate Organization 2020.

Determine the ${\mathrm{R}}_{\mathrm{f}}$ value of A1.

The rate equation for a reaction is:

rate = k[A][B]

Which mechanism is consistent with this rate equation?

A.  2A $\rightleftharpoons$ I       Fast
     I + B → P    Slow

B.  A + B $\rightleftharpoons$ I   Fast
     I + A → P    Slow

C.  A → I          Slow
     I + B → P    Fast

D.  B $\rightleftharpoons$ I         Fast
     I + A → P    Slow

A student performed an experiment to find the melting point of sulfur, obtaining 118.0 °C. The literature value is 115.2 °C. What was the percentage error?

A.  $\frac{118.0-115.2}{115.2}\times 100\%$

B.  $\frac{115.2}{118.0}\times 100\%$

C.  $\frac{118.0-115.2}{118.0}\times 100\%$

D.  $\frac{118.0}{115.2}\times 100\%$

Determine the percentage uncertainty of the mass of product after heating.

Suggest an explanation, other than product being lost from the crucible or reacting with nitrogen, that could explain the yield found in (b)(iii).

Determine the percentage uncertainty of the mass of product after heating.

Suggest an explanation, other than product being lost from the crucible or reacting with nitrogen, that could explain the yield found in (b)(iii).

20 cm³ of 1 mol dm⁻³ sulfuric acid was added dropwise to 20 cm³ of 1 mol dm⁻³ barium hydroxide producing a precipitate of barium sulfate.

H₂SO₄(aq) + Ba(OH)₂(aq) → 2H₂O (l) + BaSO₄(s)

Which graph represents a plot of conductivity against volume of acid added?

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of
formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of
formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

The experiment gave an error in the rate because the pressure gauge was inaccurate.

Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

The experiment gave an error in the rate because the pressure gauge was inaccurate.

Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

The dotted line represents the formation of oxygen, O₂ (g), from the uncatalysed complete decomposition of hydrogen peroxide, H₂O₂ (aq).

Which curve represents a catalysed reaction under the same conditions?

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

The uncertainty of the 100.0cm³ volumetric flask used to make the solution was ±0.6cm³.

Calculate the maximum percentage uncertainty in the mass of NaHCO₃ so that the concentration of the solution is correct to ±1.0 %.

The uncertainty of the 100.0cm³ volumetric flask used to make the solution was ±0.6cm³.

Calculate the maximum percentage uncertainty in the mass of NaHCO₃ so that the concentration of the solution is correct to ±1.0 %.

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

In a laboratory experiment solutions of potassium iodide and hydrogen peroxide were mixed and the volume of oxygen generated was recorded. The volume was adjusted to 0 at t = 0.

The data for the first trial is given below.

Plot a graph on the axes below and from it determine the average rate of formation of oxygen gas in cm³ O₂ (g) s⁻¹.

Average rate of reaction:

Determine from the graph the rate of reaction at 20 s, in cm³ s⁻¹, showing your working.

Describe one systematic error associated with the use of the gas syringe, and how the error affects the calculated rate.

Identify one error associated with the use of an accurate stopwatch.

The experiment gave an error in the rate because the pressure gauge was inaccurate. Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

The experiment gave an error in the rate because the pressure gauge was inaccurate. Outline whether repeating the experiment, using the same apparatus, and averaging the results would reduce the error.

Estimate the time at which the powdered zinc was placed in the beaker.

State what point Y on the graph represents.

The maximum temperature used to calculate the enthalpy of reaction was chosen at a point on the extrapolated (dotted) line.

State the maximum temperature which should be used and outline one assumption made in choosing this temperature on the extrapolated line.

Maximum temperature:

Assumption:

To determine the enthalpy of reaction the experiment was carried out five times. The same volume and concentration of copper(II) sulfate was used but the mass of zinc was different each time. Suggest, with a reason, if zinc or copper(II) sulfate should be in excess for each trial.

Predict, giving a reason, how the final enthalpy of reaction calculated from this experiment would compare with the theoretical value.

Determine from the graph the rate of reaction at 20 s, in cm³ s⁻¹, showing your working.

Describe one systematic error associated with the use of the gas syringe, and how the error affects the calculated rate.

Identify one error associated with the use of an accurate stopwatch.

The dotted line represents the formation of oxygen, O₂(g), from the uncatalysed complete decomposition of hydrogen peroxide, H₂O₂ (aq).

Which curve represents a catalysed reaction under the same conditions?

Data collected from a larger number of silicon samples could also be plotted to determine the density using the following axes.

Which statements are correct?

    I. The density is the slope of the graph.
    II. The data will show that mass is proportional to volume.
    III. The best-fit line should pass through the origin.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Estimate the time at which the powdered zinc was placed in the beaker.

State what point Y on the graph represents.

The maximum temperature used to calculate the enthalpy of reaction was chosen at a point on the extrapolated (dotted) line.

State the maximum temperature which should be used and outline one assumption made in choosing this temperature on the extrapolated line.

Maximum temperature:

Assumption:

To determine the enthalpy of reaction the experiment was carried out five times. The same volume and concentration of copper(II) sulfate was used but the mass of zinc was different each time. Suggest, with a reason, if zinc or copper(II) sulfate should be in excess for each trial.

Predict, giving a reason, how the final enthalpy of reaction calculated from this experiment would compare with the theoretical value.

Which graph would not show a linear relationship for a fixed mass of an ideal gas with all other variables constant?

A. P against V

B. P against $\frac{1}{\text{V}}$

C. P against T

D. V against T

Calculate the percentage uncertainty of the day 5 titre.

Calculate the percentage uncertainty of the day 5 titre.

Determine the initial rate of reaction of limestone with nitric acid from the graph.

Show your working on the graph and include the units of the initial rate.

Explain why the rate of reaction of limestone with nitric acid decreases and reaches zero over the period of five days.

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

Formulate an equation for the reaction of one mole of phosphoric acid with one mole of sodium hydroxide.

K_c for 2N₂O (g) $\rightleftharpoons$ 2N₂ (g) + O₂ (g) is 7.3 × 10³⁴.

What is K_c for the following reaction, at the same temperature?

N₂ (g) + $\frac{1}{2}$O₂ (g) $\rightleftharpoons$ N₂O (g)

A. 7.3 × 10³⁴

B. $\frac{1}{\sqrt{7.3\times {10}^{34}}}$

C. $\frac{2}{7.3\times {10}^{34}}$

D. $\frac{1}{2\times 7.3\times {10}^{34}}$

Determine the density of calcium, in g cm⁻³, using section 2 of the data booklet.

Ar = 40.08; metallic radius (r) = 1.97 × 10⁻¹⁰ m

Calculate the percentage uncertainty and percentage error in the experimentally determined value of $K_{\mathrm{c}}$ for methanol.

Comment on the magnitudes of random and systematic errors in this experiment using the answers in (e).

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Proteins are polymers of amino acids.

A paper chromatogram of two amino acids, A1 and A2, is obtained using a non-polar solvent.

© International Baccalaureate Organization 2020.

Determine the ${\mathrm{R}}_{\mathrm{f}}$ value of A1.

Which properties can be monitored to determine the rate of the reaction?

Fe (s) + CuSO₄ (aq) → Cu (s) + FeSO₄ (aq)

    I. change in volume
    II. change in temperature
    III. change in colour

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Which graph represents the relationship between the rate constant, $k$, and temperature, $T$, in kelvin?

Proteins are polymers of amino acids. A paper chromatogram of two amino acids, A1 and A2, is obtained using a non-polar solvent.

© International Baccalaureate Organization 2020.

Determine the ${\mathrm{R}}_{\mathrm{f}}$ value of A1.

The rate equation for a reaction is:

rate = k[A][B]

Which mechanism is consistent with this rate equation?

A.  2A $\rightleftharpoons$ I       Fast
     I + B → P    Slow

B.  A + B $\rightleftharpoons$ I   Fast
     I + A → P    Slow

C.  A → I          Slow
     I + B → P    Fast

D.  B $\rightleftharpoons$ I         Fast
     I + A → P    Slow