GCE
Chemistry B
H433/02: Scientific literacy in chemistry
*1350316499*
A Level
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Use the Insert to answer Question 5.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 100.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 20 pages.
ADVICE
• Read each question carefully before you start your answer.
© OCR 2024 [601/5371/4] DC (LK/SG) 332659/4
OCR is an exempt Charity
Turn over
1 Trans fats are made from carboxylic acids with double bonds in a trans
arrangement. They sometimes improve the texture of foods, but they are harmful
to health.
(a) Fig. 1.1 shows the structure of a fat molecule.
Fig. 1.1
H 2C O A
HC O O B
H 2C O O
C
O
, 2
(i) The side-chains formed by three carboxylic acids are labelled A, B and C.
Give the letter of the side-chain that is:
Saturated ...............
Trans unsaturated ...............
(ii) The fat molecule in Fig. 1.1 can be represented as shown below.
Complete the equation for the hydrolysis of the fat with aqueous NaOH.
H O
H C O C R'
O
H C O C R''
O
H C O C R'''
H
(b) Long-chain carboxylic acids can be identified by converting them to their methyl esters
and then using gas–liquid chromatography.
Write the equation for the conversion of RCOOH to its methyl ester using the appropriate
alcohol.
[2] (c) In gas–liquid chromatography, the methyl esters are injected into a stream of
carrier gas and passed through a column containing the stationary phase.
(i) Name a suitable carrier gas.
...............................................................................................................................................
...... [1]
(ii) What does the stationary phase consist of?
...............................................................................................................................................
...........
...............................................................................................................................................
...... [2]
(iii) Mass spectrometry can be used to identify the emerging esters.
Which property of the esters does mass spectrometry measure?
© OCR 2024
, 3
...............................................................................................................................................
...... [1]
(d) Oils are fats which are liquid at room temperature. Many oils are made from palmitic
and stearic acids, as well as other carboxylic acids.
To identify an oil, the methyl esters of the carboxylic acids, including methyl palmitate
and methyl stearate, are made from the oil.
The oil can be identified from the gas–liquid chromatogram of the methyl esters using
the ratio of methyl palmitate:methyl stearate from the peak heights.
Linseed oil has a methyl palmitate:methyl stearate ratio of 5:4.
Use the gas–liquid chromatograms below to decide which of the oils D, E or F is
linseed oil. Give your reasoning.
pure pure oil D oil E
methyl palmitate methyl stearate
................................................................................................................................
...................
................................................................................................................................
...................
................................................................................................................................
...................
................................................................................................................................
...................
................................................................................................................................
...................
................................................................................................................................
...................
................................................................................................................................
.............. [4]
(e) Oleic acid, C18H34O2, has the structural formula CH3(CH2)7CH=CH(CH2)7COOH.
(i) The iodine value of a fat or carboxylic acid is the mass of iodine that will combine with
100 g of the substance, saturating the double bonds.
© OCR 2024 Turn over
, 4
Calculate the iodine value of oleic acid.
iodine value = ...................................................... g
(ii) A student suggests treating oleic acid with steam and H 3PO4, using high temperature
and pressure.
The student says that the product will be
CH3(CH2)7CH(OH)CH(OH)(CH2)7COOH.
Comment on the student’s statement.
...............................................................................................................................................
...........
...............................................................................................................................................
...........
...............................................................................................................................................
...........
...............................................................................................................................................
...... [2]
2 This question is about some substances used as medicines.
(a)
(i) People use magnesium carbonate to neutralise excess stomach acid.
Magnesium carbonate reacts with hydrochloric acid in the stomach as shown in the
equation.
MgCO3(s) + 2HCl (aq) MgCl 2(aq) + CO2(g) + H2O(I)
A tablet contains 305 mg of MgCO3.
Calculate the volume of CO2 (in cm3) produced by this tablet at RTP.
Give your answer to an appropriate number of significant figures.
© OCR 2024
Chemistry B
H433/02: Scientific literacy in chemistry
*1350316499*
A Level
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Use the Insert to answer Question 5.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 100.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 20 pages.
ADVICE
• Read each question carefully before you start your answer.
© OCR 2024 [601/5371/4] DC (LK/SG) 332659/4
OCR is an exempt Charity
Turn over
1 Trans fats are made from carboxylic acids with double bonds in a trans
arrangement. They sometimes improve the texture of foods, but they are harmful
to health.
(a) Fig. 1.1 shows the structure of a fat molecule.
Fig. 1.1
H 2C O A
HC O O B
H 2C O O
C
O
, 2
(i) The side-chains formed by three carboxylic acids are labelled A, B and C.
Give the letter of the side-chain that is:
Saturated ...............
Trans unsaturated ...............
(ii) The fat molecule in Fig. 1.1 can be represented as shown below.
Complete the equation for the hydrolysis of the fat with aqueous NaOH.
H O
H C O C R'
O
H C O C R''
O
H C O C R'''
H
(b) Long-chain carboxylic acids can be identified by converting them to their methyl esters
and then using gas–liquid chromatography.
Write the equation for the conversion of RCOOH to its methyl ester using the appropriate
alcohol.
[2] (c) In gas–liquid chromatography, the methyl esters are injected into a stream of
carrier gas and passed through a column containing the stationary phase.
(i) Name a suitable carrier gas.
...............................................................................................................................................
...... [1]
(ii) What does the stationary phase consist of?
...............................................................................................................................................
...........
...............................................................................................................................................
...... [2]
(iii) Mass spectrometry can be used to identify the emerging esters.
Which property of the esters does mass spectrometry measure?
© OCR 2024
, 3
...............................................................................................................................................
...... [1]
(d) Oils are fats which are liquid at room temperature. Many oils are made from palmitic
and stearic acids, as well as other carboxylic acids.
To identify an oil, the methyl esters of the carboxylic acids, including methyl palmitate
and methyl stearate, are made from the oil.
The oil can be identified from the gas–liquid chromatogram of the methyl esters using
the ratio of methyl palmitate:methyl stearate from the peak heights.
Linseed oil has a methyl palmitate:methyl stearate ratio of 5:4.
Use the gas–liquid chromatograms below to decide which of the oils D, E or F is
linseed oil. Give your reasoning.
pure pure oil D oil E
methyl palmitate methyl stearate
................................................................................................................................
...................
................................................................................................................................
...................
................................................................................................................................
...................
................................................................................................................................
...................
................................................................................................................................
...................
................................................................................................................................
...................
................................................................................................................................
.............. [4]
(e) Oleic acid, C18H34O2, has the structural formula CH3(CH2)7CH=CH(CH2)7COOH.
(i) The iodine value of a fat or carboxylic acid is the mass of iodine that will combine with
100 g of the substance, saturating the double bonds.
© OCR 2024 Turn over
, 4
Calculate the iodine value of oleic acid.
iodine value = ...................................................... g
(ii) A student suggests treating oleic acid with steam and H 3PO4, using high temperature
and pressure.
The student says that the product will be
CH3(CH2)7CH(OH)CH(OH)(CH2)7COOH.
Comment on the student’s statement.
...............................................................................................................................................
...........
...............................................................................................................................................
...........
...............................................................................................................................................
...........
...............................................................................................................................................
...... [2]
2 This question is about some substances used as medicines.
(a)
(i) People use magnesium carbonate to neutralise excess stomach acid.
Magnesium carbonate reacts with hydrochloric acid in the stomach as shown in the
equation.
MgCO3(s) + 2HCl (aq) MgCl 2(aq) + CO2(g) + H2O(I)
A tablet contains 305 mg of MgCO3.
Calculate the volume of CO2 (in cm3) produced by this tablet at RTP.
Give your answer to an appropriate number of significant figures.
© OCR 2024
