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Transcript
Chemistry
1.
The amino acid, alanine, dissolves in water.
In an aqueous solution with a pH = 7, alanine is acting as:
A. an acid only.
B. a base only.
C. neither an acid nor a base.
D. both an acid and a base.
2.
An aqueous mixture of two substances (Y and Z) is subjected to analysis by both
paper chromatography and high performance liquid chromatography (HPLC). In
both forms of chromatography, component Z of the mixture was bonded more
strongly to the stationary phase than component Y.
In terms of Rf and Rt, where Rt is the retention time in HPLC, component Z has
the:
A. Higher Rf Lower Rt
B. Higher Rf Higher Rt
C. Lower Rf Lower Rt
D. Lower Rf Higher Rt
3.
20.00 mL of 0.10 M sodium hydroxide is placed in a volumetric flask and titrated
with 0.10 M ethanoic acid. The volume of ethanoic acid required to react
completely with the sodium hydroxide and the approximate pH at the
equivalence point would be closest to
Volume of ethanoic acid required (mL)
pH at equivalence point
A.
less than 20.00 mL
7
B.
less than 20.00 mL
greater than 7
C.
20.00 mL
7
D.
20.00 mL
greater than 7
4.
The concentration of copper ions in ground water is to be analysed using atomic
absorption spectroscopy. A sample of the water is sprayed into a flame and a
light is passed through.
A. A zinc lamp should be used and the intensity of the light will be greater after
passing through the sample in the flame.
B. A zinc lamp should be used and the intensity of the light will reduce after
passing through the sample in the flame.
C. A copper lamp should be used and the intensity of the light will be greater
after passing through the sample in the flame.
D. A copper lamp should be used and the intensity of the light will reduce after
passing through the sample in the flame.
5.
Spectroscopic analysis of an organic compound which has the empirical formula
C2H4O, has a major peak centred at 1715 cm–1 and a short narrow peak centred
at 3100cm–1 in its infrared spectrum. Its mass spectrum shows a fragment peak
at m/e- = 29. On its 1H NMR spectrum there is a peak at δ = 4.1 ppm.
The semi-structural formula of the compound is most likely to be
A. CH3CHO
B. CH3COOH
C. CH3COOCH2CH3
D. CH3CH2CH2COOH
6.
When 50 mL of 1.0 mol L-1 nitric acid, HNO3(aq), is added to 50 mL of 1.0 mol
L-1 potassium hydroxide solution, KOH (aq), the temperature of the mixture
increases by 6.4 °C.
What should be the temperature change when 25 mL of each of these solutions
are mixed together?
A. 1.6 °C.
B. 3.2 °C.
C. 6.4 °C.
D. 12.8 °C.
7.
Consider the following formulas:
I [H3O+]2
II [OH–] x 10–pH
III [H2O] x value of K for the self-ionisation reaction of water
Which of the above could be used to determine the self-ionisation constant (Kw)
of pure water at a particular temperature?
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
8.
9.
Which of the following comparisons of fuel cells, primary cells and secondary
cells is incorrect?
A. In both fuel cells and secondary cells the electrodes act as catalysts, while in
primary cells they do not.
B. Fuels cells must be continually provided with reactants, while primary and
secondary cells contain a store of reactants.
C. Secondary cells are able to be recharged, while primary cells must be
discarded when their reactants are depleted.
D. In all three cell types, chemical energy is converted to electrical energy.
10.
Answer:
1. D
2. D
3. D
4. D
5. C
6. C
7. A
8. D
9. A
10. C