University of the Western Cape
Chemistry Department
________________________________________________________
CHEMISTRY 116
Test 2
April 2017
MARKS: 20
TIME: 11/2 Hour
 ANSWER ALL QUESTIONS.
 USE THE ANSWER SHEET PROVIDED.
 A PERIODIC TABLE IS PROVIDED.
____________________________________________________________________
1. Molecular weight of propane (C3H8) is
A.
B.
C.
44.096g/mol40.01g/mol
41.01g/mol
46.02g/mol
2. The percent, by weight, of nitrogen in ammonium sulfate, (NH4)2SO4 is:
(atomic weights: N = 14.0, H = 1.01, S = 32.1, O = 16.0)
A. 2%
B. 21.2%
C. 28.0%
D. 132%
E. 14.0%
3. The number of moles of glucose, C6H12O6, in 152 grams of C6H12O6 is:
(atomic weights: C = 12.0, H = 1.00 and O = 16.0)
A.
B.
C.
D.
E.
1.18
1.80
0.844
12.0
E. 29.0
4. The number of atoms of oxygen in 27.7 grams of aluminum nitrate, Al(NO3)3 is:
(molecular weight of Al(NO3)3 is 213)
A.
B.
C.
D.
E.
7.83 x 1022
0.130
1.17
7.05 x 1023
6.02 x 1023
5. Which one of the following statements about negative ions is incorrect?
A.
B.
C.
D.
they are also known as anions
they are formed when atoms gain electrons
they are larger than the atom from which they were formed
they are smaller than the atom from which they were formed
6. Name the compound CaF2
A. Calcium difluoride
B. Calcium bifluoride
C. Calcium fluoride
D. None of the above is correct
7. Which one of the following pairs of atoms is most likely to form an ionic compound?
A.
B.
C.
D.
Na and F
C and F
N and F
O and F
8. What is the correct formula for aluminium sulfate?
A.
B.
C.
D.
E.
AlSO4
Al2SO4 3
Al3(SO4)2
Al2(SO4)3
Al2S3O12
9. What would be the best name for K3PO4?
A.
B.
C.
D.
E.
Potassium Phosphate
Potassium (I) Phosphate
Tripotassium Phosphate
Tripotassium Monophosphorus Tetroxide
Potassium Phosphide Oxide
10. A compound is 40.0 % carbon, 53.3 % oxygen, and 6.7 % hydrogen. What is its empirical
formula?
A. C4O5H7
B.C1O2H3
C. C1O1H2
D. More than one could be the correct empirical formula.
E.None of these is the correct empirical formula.
11. If the compound in problem 10 has a molecular weight equal to 60.0 g/mol, what is the
molecular formula?
A C3O1H6
B C1O2H16
C C2O2H4
D More than one could be the correct molecular formula.
E None of these is the correct molecular formula.
12. Which of the following is a balanced chemical equation?
A. H2O2 →H2O + O2
B. 2 Fe2O3 + 3 C →4Fe + 3CO2
C. SO2 + O2 + 2H2O → 4H2SO4
D. 2 Mg + HCl →MgCl2 + H2
13. The combustion of propane (C3H8) in the presence of excess oxygen yields CO2 and H2O:
C3H8 (g) + 5O2 (g) → 3CO2 (g) + 4H2O (g)
When 2.5 mol of O2 are consumed in their reaction, __________ mol of CO2 are produced.
A) 1.5
B) 2.5
C) 5.0
D) 6.0
E) 3.0
Consider the following chemical reaction for problems, 14, 15, 16, 17, 18
_Cl2 (g) +
_ KBr (l) →
_ KCl(s) +
_Br2 (g)
14. Balance this reaction
A. Cl2 + KBr →KCl + Br2
B. Cl2 + 2 KBr →2 KCl + Br2
C. Cl2 + KBr → 2 KCl + Br2
D. Cl2 + 2 KBr →KCl + Br2
15. How many grams of bromine should form from the reaction of 40.0 grams of potassium
bromide and 10.0g of chlorine
A. 13.4g
B. 45.0g
C. 22.5g
D. 26.8g
E. None of the above is correct
16. If in the lab you perform an experiment, and you were able to collect 20.5g of bromine for
this rxn., what is your percentage yield?
A.76.4%
B.45.6%
C. 91.1%
D. 54.3%
17. How much excess reactant would react during this experiment.
A. 33.6g
B.20.0.g
C.45.06g
D 11.9g.
18. How much of the excess reactant will be left over, unreacted?
A. 8.75g
B. 11.2g
C.6.44g
D.8.08g
19. A solution is prepared by dissolving 25.0 g of NaCl (formula wt = 58.5) in enough water
to make 350 mL of solution. The molarity of the solution is:
A. 1.22 M
B. 71.4 M
C. 0.00122 M
D. 0.0714 M
E. 0.819 M
20. Consider the titration involving the following reaction:
Ba(NO3)2 + Na2SO4 →Ba SO4 + 2NaNO3
25.00 mL of Na2SO4 was placed in a flask. This solution was titrated with 0.1500 M Ba(NO3)2
solution. It was found that 30.00 mL of Ba(NO3)2 was needed for complete reaction. Calculate
the molarity of the Na2SO4 solution.
A. 0.125 M
B. 0.0900 M
C. 360 M
D. 0.150 M
E. 0.180 M
END OF QUESTIONS!!!!
INFORMATION SHEET
N = 6.022 x 1023 mol-1
A
𝐶𝑖 𝑉𝑖 = 𝐶𝑓 𝑉𝑓
𝑐=
𝑛
𝑣