Chemistry (XXXXX)
College of Technology (COLTECH)
Semester: First Semester
Level: 200
Year: 2014
CONTINUOUS ASSESSMENT FOR APPLIED GENERTAL CHEMISTRY JANUARY 2015
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1. What does chemistry study?
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2. Classify matter
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3. What is the basis used to classify matter in states?
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4. Define the following terms:
Pure substance
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Compound………………………………………………………………………………………………………………………………
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Mixture ………………………………………………………………………………………………………………………………….
5. Classify the following in increasing number N of atoms of each sample: 1g of Sodium (
23
Na),
1g of Potassium (
39
K), 1g of Iron (
56
Fe)…………………………………………………………………………………….
6. Classify the following in increasing number of molecules of each sample: 27g of H
2
O
(l)
,3
moles of CH
4(g)
, 22.4l of CO
2(g)
at stp……………………………………………………………………..…………………
7. Consider the following representations: A =
12
6
C; B =
14
6
C; D =
12
7
C. a) Which of them is (are)
not correct? ……………… explain why
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b) for each correct representation, give the number of neutrons in the nucleus:
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8. The element rhenium, with two naturally-occurring isotopes
185
Re and
187
Re, has a relative
atomic mass of 186.207 au. Calculate the natural abundance of each of each isotope given
that their atomic masses are respectively 184.953 and 186.956
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THE REPUBLIC OF CAMEROUN
Peace-Work-Fatherland
THE UNIVERSITY OF BAMENDA
COLLEGE OF TECHNOLOGY
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9. State the law of conservation of mass
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Use the law to calculate the mass of potassium chloride produced during the reaction
between 1.205g of potassium and 6.815g of chlorine if 3.300g of chlorine remains
unreacted………………………………………………………………………………………………………………………………
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10. When iron rusts, its mass increases. When a matchstick burns, the mass of the ash is less. Do
these observations violate the law of conservation of mass? explain
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11. The brominating reaction of 15.0g Butanol C
4
H
9
OH, 19.4g of Sodium Bromide NaBr and
32.7g Sulphuric Acid H2SO4 yields 17.1g of C
4
H
9
Br. Which of these reactants is the limiting
reagent? Explain
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Calculate the theoretical yield, the actual yield and the percentage yield
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12. The analysis of a given compound shows that it contains 30.45% carbon, 20.03% of oxygen,
45.69% of chlorine and hydrogen. The vapour density of the compound is 5.42 times the
density of air under normal conditions of temperature and pressure. What are the empirical,
molecular and structural formulas of the
compound?..................................................................................................................................
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13. What is the ΔHﹾ
vap
of a liquid that has a vapour pressure of 641 torr at 85.2ﹾC and a boiling
point of 95.6°C at 1 atm?
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