DP Chemistry (last assessment 2024)

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Question 23M.3.SL.TZ1.12

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Date May 2023 Marks available [Maximum mark: 10] Reference code 23M.3.SL.TZ1.12
Level SL Paper 3 Time zone TZ1
Command term Deduce, Describe, Explain, Identify, State Question number 12 Adapted from N/A
12.
[Maximum mark: 10]
23M.3.SL.TZ1.12

Drugs are commonly prescribed by medical professionals to treat illness.

(a)

State two different drug administration methods.

[1]

Markscheme

Any two of:
oral ✓
inhalation ✓
topical/applied to the skin ✓
parenteral/injection ✓
suppositories ✓
eye/ear drops ✓

 

One mark for any two correct methods.

Count multiple methods of injection (intramuscular, subcutaneous, intravenous) as just one method.

(b)

Describe one similarity and one difference between the therapeutic index in animal and human studies.

 

Similarity: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  

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Difference: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

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[2]

Markscheme

Similarity:
both are the ratio between a dose that would cause harm and that required to have an effect
OR
calculation to divide TD or LD by the effective dose/ED ✓

Difference:
toxic dose/TD «for 50 %/(TD50)» used for human population AND lethal dose/LD «for 50 %/(LD50)» used for animal population ✓

 

Accept both involve ED/Effective Dose.

Accept both compare dose that would cause harm and that required to have an effect for M1.

(c)

Explain how aspirin works as a mild analgesic.

[2]

Markscheme

interferes with pain at source «of injury» ✓
prevents release of prostaglandins/substances causing swelling/pain ✓

(d)

Deduce the structural formulae of the missing reactant A and product B in the synthesis of aspirin from salicylic acid.

[2]

Markscheme

ALTERNATIVE 1:
A: CH3COOCOCH3 ✓
B: CH3COOH ✓

ALTERNATIVE 2:
A: CH3COOH ✓
B: H2O ✓

ALTERNATIVE 3:
A: CH3COCl ✓
B: HCl ✓

 

Accept expanded structural formulas.

(e)

Opiates are another class of drug found in nature. Identify the naturally occurring source of opiates.

[1]

Markscheme

«opium» poppy ✓

(f)

State one advantage and one disadvantage of prescribing opiates to patients.

 

Advantage: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

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Disadvantage: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

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[2]

Markscheme

Advantage:
strong/severe/surgical pain relief
OR
stops coughing reflex
OR
fast action ✓

Disadvantage:
addiction
OR
constipation
OR
tolerance «leading to overdose» ✓

 

Accept strong painkillers/analgesics for M1.

Accept constipation for M1 if not given as a disadvantage.

Accept small therapeutic window for M2.
Accept other named specific side effect for M2.