1.
State what is meant by infrared spectroscopy.
[1 mark]
- bonds absorb characteristic wavenumbers
JD SCIENCE
Analytical chemistry
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
2.
State what is meant by mass spectrometry.
[1 mark]
- molecular ion gives Mr
3.
State what is meant by ¹H NMR.
[1 mark]
- chemical shift, integration, splitting
4.
State what is meant by ¹³C NMR.
[1 mark]
- number of environments
5.
State what is meant by a chromatographic method.
[1 mark]
- TLC, GC, column
6.
State what is meant by an aromatic compound.
[1 mark]
- delocalised π ring
7.
State what is meant by phenol.
[1 mark]
- OH on a benzene ring
8.
State what is meant by an acyl chloride.
[1 mark]
- very reactive carbonyl
9.
State what is meant by a polymer from condensation.
[1 mark]
- polyester or polyamide
10.
State what is meant by a synthetic route.
[1 mark]
- planning reagents and conditions
11.
Jac is asked about infrared spectroscopy in a Eduqas Chemistry paper.
(a) [2 marks]
- C=O around 1700 cm⁻¹, O–H broad
(b) [3 marks]
- fingerprint region
12.
Jac is asked about mass spectrometry in a Eduqas Chemistry paper.
(a) [2 marks]
- fragmentation pattern
(b) [3 marks]
- high-resolution gives formula
13.
Jac is asked about ¹H NMR in a Eduqas Chemistry paper.
(a) [2 marks]
- n+1 rule
(b) [3 marks]
- TMS standard
14.
Jac is asked about ¹³C NMR in a Eduqas Chemistry paper.
(a) [2 marks]
- no splitting usually
(b) [3 marks]
- used with ¹H NMR
15.
Jac is asked about a chromatographic method in a Eduqas Chemistry paper.
(a) [2 marks]
- retention time / Rf
(b) [3 marks]
- separates mixtures
16.
Jac is asked about an aromatic compound in a Eduqas Chemistry paper.
(a) [2 marks]
- electrophilic substitution
(b) [3 marks]
- benzene is more stable than expected
17.
A molecular ion is at m/z 46. Possible formula
[3 marks]
- Final answer: C₂H₆O (ethanol)
18.
Two peaks in ¹³C NMR for C₂H₆O could mean
[3 marks]
- Final answer: two carbon environments (ethanol)
19.
Splitting of a CH₃ next to CH₂
[3 marks]
- Final answer: triplet
20.
IR: a broad peak at 3200–3600 cm⁻¹ suggests
[3 marks]
- Final answer: O–H (alcohol or acid)
21.
A tripeptide has how many peptide bonds
[3 marks]
- Final answer: 2
22.
GC peak area is 20% of total. Estimate % of that component
[3 marks]
- Final answer: 20%
23.
Jac carries out a Eduqas-style required practical linked to organic analysis and modern techniques. This is a typical Eduqas required-practical style question.
(a) [2 marks]
- Independent: the independent variable for this topic
- Dependent: the measured outcome
(b) [2 marks]
- keep all other variables constant
- so the test is fair / only one variable is changed
(c) [2 marks]
- repeat and calculate a mean / use a tighter method
24.
Jac carries out collecting valid data for organic analysis and modern techniques. This is a typical Eduqas required-practical style question.
(a) [2 marks]
- Independent: a chosen factor
- Dependent: a quantitative measurement
(b) [2 marks]
- calibrated instrument
- so the test is fair / only one variable is changed
(c) [2 marks]
- systematic error from zero error
25.
Jac carries out drawing a graph for organic analysis and modern techniques. This is a typical Eduqas required-practical style question.
(a) [2 marks]
- Independent: x-variable
- Dependent: y-variable
(b) [2 marks]
- same scale / same apparatus
- so the test is fair / only one variable is changed
(c) [2 marks]
- not drawing a line of best fit through the trend
26.
Jac carries out evaluating a method about organic analysis and modern techniques. This is a typical Eduqas required-practical style question.
(a) [2 marks]
- Independent: method change
- Dependent: precision / accuracy
(b) [2 marks]
- same sample size
- so the test is fair / only one variable is changed
(c) [2 marks]
- too few repeats
27.
Compare infrared spectroscopy with mass spectrometry.
[4 marks]
- bonds absorb characteristic wavenumbers
- molecular ion gives Mr
- give one linked difference
28.
Compare mass spectrometry with ¹H NMR.
[4 marks]
- molecular ion gives Mr
- chemical shift, integration, splitting
- give one linked difference
29.
Compare ¹H NMR with ¹³C NMR.
[4 marks]
- chemical shift, integration, splitting
- number of environments
- give one linked difference
30.
Compare ¹³C NMR with a chromatographic method.
[4 marks]
- number of environments
- TLC, GC, column
- give one linked difference
31.
Apply your knowledge of phenol to this situation: weaker acid than carboxylic acids, stronger than alcohols
[3 marks]
- weaker acid than carboxylic acids, stronger than alcohols
32.
Apply your knowledge of an acyl chloride to this situation: nucleophilic addition–elimination
[3 marks]
- nucleophilic addition–elimination