NSS Chemistry Part 15 Analy HKCEE and HKAL Past Pap 1. HKCEE 1994 Q8b A student carried out some tests on summarized in the following flow d (i) Based on the above inform (ii) Describe how the flame tes 1 ytical Chemistry (Structural Questio per Questions n an ionic compound X which was a white solid diagram: mation, deduce the cation and anion present in X. st on X can be carried out in the laboratory. ons) d. The results obtained were (6 marks)
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
NSS Chemistry Part 15 Analytical Chemistry
HKCEE and HKAL Past Paper Questions
1. HKCEE 1994 Q8b
A student carried out some tests on an ionic compound
summarized in the following flow diagram:
(i) Based on the above information, deduce the cation and anion present in
(ii) Describe how the flame test on
1
NSS Chemistry Part 15 Analytical Chemistry (Structural Questions)
Past Paper Questions
A student carried out some tests on an ionic compound X which was a white solid. The results obtained were
summarized in the following flow diagram:
Based on the above information, deduce the cation and anion present in X.
Describe how the flame test on X can be carried out in the laboratory.
(Structural Questions)
which was a white solid. The results obtained were
(6 marks)
2
2. HKCEE 1995 Q2
In each of the following groups of substances, there is ONE substance which is different from the other in
terms of their properties. In each group, identify the substance which is different from the others and explain
your choice.
a. argon, fluorine, helium, neon
b. nylon, perspex, polyethene, urea-methanal
c. milk of magnesia, soap, vinegar, window cleaner
d. carbon monoxide, hydrogen, methane, nitrogen
(8 marks)
3. HKCEE 1996 Q6b
A, B, C and D are four unlabelled bottles, each containing one of the following reagents:
2M ammonia solution, 2M ethanoic acid,
2M hydrochloric acid, 2M nitric acid
The following scheme is used to identify the four reagents:
(i) What is the reagent in bottle A? Expl
(ii) What is the reagent in bottle B? Write a chemical equation for the reaction between this reagent and copper
turnings, and a chemical equation for the formation of the brown fumes.
(iii) (1) Suggest a test to distinguish between the reagent in bottles
(Smelling the reagents in NOT
(2) State the observable change in this test and explain your answer.
3
are four unlabelled bottles, each containing one of the following reagents:
2M ammonia solution, 2M ethanoic acid,
2M hydrochloric acid, 2M nitric acid
The following scheme is used to identify the four reagents:
? Explain why this reagent turns red litmus paper blue.
? Write a chemical equation for the reaction between this reagent and copper
turnings, and a chemical equation for the formation of the brown fumes.
Suggest a test to distinguish between the reagent in bottles C and D.
NOT an acceptable answer.)
State the observable change in this test and explain your answer.
are four unlabelled bottles, each containing one of the following reagents:
ain why this reagent turns red litmus paper blue.
? Write a chemical equation for the reaction between this reagent and copper
(8 marks)
4
5
4. HKCEE 1998 Q5
Each of five unlabelled bottles contains one of the following chemicals:
2 M hydrochloric acid 2 M nitric acid
2 M sodium chloride solution 2 M sodium hydroxide solution
distilled water
Suggest how you would carry out tests to identify the contents of each bottles, using the materials and
apparatus listed below. Your answer should include the observation of each test.
Copper foil, solid copper(II) carbonate, 2 M copper(II) chloride solution,
test tubes and a Bunsen burner
(You are Not required to write chemical equations. Answer in the form of flow diagrams will NOT be
marked.)
(8 marks)
5. HKCEE 1999
The diagram below shows a bottle of chemical waste in a school laboratory.
Describe and explain how you would remove kerosene and iron(III) ions from the chemical waste.
(You may use any apparatus and chemicals available in a school laboratory.)
6
The diagram below shows a bottle of chemical waste in a school laboratory.
Describe and explain how you would remove kerosene and iron(III) ions from the chemical waste.
(You may use any apparatus and chemicals available in a school laboratory.)
Describe and explain how you would remove kerosene and iron(III) ions from the chemical waste.
(8 marks)
7
6. HKCEE 2003 Q7c
Explain why filtration can be used to remove mud particles from muddy water, but cannot be used to remove
sodium chloride from sea water.
(3 marks)
7. HKCEE 2004 Q2
For each of the following pairs of substances, suggest a chemical test to distinguish one substance from the
other and state the expected observations.
(a) table salt and white sugar
(b) ammonium chloride and potassium chloride
(c) dilute sulphuric acid and dilute nitric acid
(6 marks)
a. Treat the substances with conc. H2SO4.
White sugar turns black, while slat gives misty fumes.
b. Warm the substances with NaOH.
NH4Cl(s) reacts with NaOH(aq) to give an alkaline gas, while KCl(s) does not.
c. Heat the acids with copper metal.
Only HNO3(aq) gives gas bubbles.
Sea water is a solution while muddy water is a suspension. The size of ions in sea water is much
smaller than that of the mud particles in muddy water.
Ions in sea water can pass through pores in filter device while particles cannot.
8
8. HKCEE 2004 Q8c
A policeman suspected a car driver to have drunk an excessive amount of alcoholic drinks, and used a
dichromate breathalyser to conduct a test on the driver’s breath. The result was positive.
(i) State the principle underlying the test of ethanol using a dichromate breathalyser.
(ii) The driver claimed that he had just rinsed his mouth using ethanol-containing mouthwash. Without
using other instruments, suggest how the policeman could check whether the driver’s claim was valid
or not. Explain your answer.
(4 marks)
9. HKCEE 2005 Q1a
Calcium is an element in Group II of he Periodic Table.
(i) Calcium reacts with nitrogen to form calcium nitride, which is an ionic compound. Draw the
electronic diagram of calcium nitride, showing electrons in the outermost shells only.
(ii) Suggest a test to show that marble is a calcium-containing substance.
(3 marks)
(i) Ethanol can reduce Cr2O7-2
(orange) to Cr3+
(green).
(ii) Conduct the test after the driver has thoroughly rinsed his mouth with water. A positive result probably
indicates that the driver has drunk.
Ethanol is soluble in water. The concentration of ethanol in the breath will drop after the driver has
rinsed his mouth.
9
10. HKCEE 2005 Q12
There are four unlabelled bottles each containing one of the white solids listed below:
ammonium chloride, ammonium nitrate, sodium hypochlorite and sodium sulphate
Suggest how you would carry out tests to distinguish the four solids from one another.
(9 marks)
10
11. HKCEE 2006 Q4
An aqueous solution V is known to contain the following four cations:
NH4+(aq), K
+(aq), Fe
3+(aq) and Ag
+(aq)
The flow diagram below outlines a series of tests that can be used to detect the presence of two of the above
cations in V:
(a) Write an ionic equation, with state symbols, for the formation of W from V. (1 mark)
(b) Suggest an experimental method that can be used to separate X from W. (1 mark)
(c) Name Y. (1 mark)
(d) Z still contains two of the above-mentioned cations. Is it possible to show experimentally the presence of
each of these cations in Z? Explain the answer. (2 marks)
(e) Based on the above information, suggest a colour for V. (1 mark)
11
12. HKCEE 2007 Q7
This question involves how to distinguish four unlabelled test tubes, each containing one of the following