DP Chemistry (last assessment 2024)

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Question 23M.3.HL.TZ2.27

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Date May 2023 Marks available [Maximum mark: 5] Reference code 23M.3.HL.TZ2.27
Level HL Paper 3 Time zone TZ2
Command term Identify, Predict Question number 27 Adapted from N/A
27.
[Maximum mark: 5]
23M.3.HL.TZ2.27

Ethanol can be identified by a variety of analytical techniques.

(a)

Predict the structures of three possible fragments you would expect from the mass spectrum of ethanol.

[3]

Markscheme

Any three of:
CH3CH2OH+ ✓
CH3CH2+ ✓
CH3+ ✓
CH2OH+/CH3O+ ✓
OH+ ✓

 

Penalize missing charge once only.

Accept any other reasonable fragments or m/z values.

(b)

Identify the two products formed when acidified potassium dichromate (VI), K2Cr2O7, is used in a breathalyser test.

[2]

Markscheme

Any two of:
ethanoic acid ✓
chromium(III) ✓
water ✓

 

Accept “ethanal” for M1.
Accept correct name or formula.
Accept systematic name or preferred IUPAC name (e.g. “acetic acid” OR “acetaldehyde”).
Accept any chromium(III) salt for M2.