DP Chemistry (last assessment 2024)

Question 18M.3.hl.TZ2.8f

Date	May 2018	Marks available	[Maximum mark: 1]	Reference code	18M.3.hl.TZ2.8f
Level	hl	Paper	3	Time zone	TZ2
Command term	Calculate	Question number	f	Adapted from	N/A

[Maximum mark: 1]

18M.3.hl.TZ2.8f

Amino acids are the building blocks of proteins.

(f)

UV-Vis spectroscopy can be used to determine the unknown concentration of a substance in a solution.

Calculate the concentration of an unknown sample of pepsin with an absorbance of 0.725 using section 1 of the data booklet.

Cell length = 1.00 cm

Molar absorptivity (extinction coefficient) of the sample = 49650 dm³ cm⁻¹ mol⁻¹

[1]

Markscheme

« $\frac{{0.725}}{{49650{\text{ d}}{{\text{m}}^3}\;{\text{c}}{{\text{m}}^{ - 1}}\;{\text{mo}}{{\text{l}}^{ - 1}} \times 1.00\,{\text{cm}}}} =$ » 1.46 × 10⁻⁵ «mol dm⁻³»

[1 mark]

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Options » B: Biochemistry » B.7 Proteins and enzymes (HL only)

Options » B: Biochemistry

Question 18M.3.hl.TZ2.8f

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