Multiple Choice Questions
1. A pure substance can only be
(1) a compound(2) an element
(3) an element or a compound
(4) a heterogeneous mixture
2. Two students, X and Y, reported the mass of the same substance as 7.0 g and 7.00 g, respectively. Which of the following statement is correct?
(1) Both are equally accurate
(2) X is more accurate than Y
(3) Y is more accurate than X
(4) Both are inaccurate scientifically
3. The number of significant figures in 0.0500 is
(1) one (2) three
(3) two (4) four
4. The number of significant figures in π is
(1) one (2) two
(3) three (4) infinite
5. Oxygen combines with two isotopes of carbon, 12C and 14C, to form two samples of carbon dioxide. The data illustrates
(1) Law of conservation of mass
(2) Law of multiple proportions
(3) Law of reciprocal proportions
(4) None of these
6. 6 g of carbon combines with 32 g of sulphur to form CS2. 12 g of C also combine with 32 g of oxygen to form carbon dioxide. 10 g of sulphur combines with 10 g of oxygen to form sulphur dioxide. Which law is illustrated by them?
(1) Law of multiple proportions
(2) Law of constant composition
(3) Law of reciprocal proportions
(4) Gay Lussac’s law
7. Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen. The weight of lead was obtained from the other oxide. The data illustrates
(1) Law of reciprocal proportions
(2) Law of constant proportions
(3) Law of multiple proportions
(4) Law of equivalent proportions
8. SO2 gas was prepared by (i) burning sulphur in oxygen, (ii) reacting sodium sulphite with dilute H2SO4 and (iii) heating copper with conc. H2SO4. It was found that in each case sulphur and oxygen combined in the ratio of 1:1. The data illustrate the law of
(1) Conservation of mass (2) Multiple proportions
(3) Constant proportions (4) Reciprocal proportions
9. Element A reacts with oxygen to form a compound A2O3. If 0.359 gram of a compound contains 0.128 g of oxygen, atomic weight of A will be
(1) 51 amu (2) 43.08 amu
(3) 49.7 amu (4) 47.9 amu
10. 18 g of water contains
(1) 1 g atom of hydrogen atom
(2) 2 g atom of hydrogen atom
(3) 3 g atom of hydrogen atom
(4) None of these
11. Volume at NTP of 0.44 g of CO2 is the same as that of
(1) 0.02 g of H2
(2) 0.085 g of NH3
(3) 320 mg of gaseous SO2
(4) All the above
12. A piece of copper weighs 0.635 g. How many atoms of copper does it contain?
(1) 6.02 x 1022 electrons
(2) 6.02 x 1021 electrons
(3) 6.023 x 1023 electrons
(4) 6.012 x 1024 electrons
13. Which of the following pairs of gases contain the same number of molecules?
(1) 16 g of O2, 14 g of N2
(2) 8 g of O2, 22 g of CO2
(3) 28 g of N2, 22 g of CO2
(4) 32 g of O2, 32 g of N2
14. A glass of juice contains 9 g of glucose. The number of carbon atoms in the glass of juice is
(1) 1.8069 x 1023 (2) 1.5012 x 1023
(3) 2.5012 x 1023 (4) None
15. Weight of 6.023 x 1021 atoms of zinc (At. wt. of Zn = 65.4) is
(1) 0.645 g (2) 0.0654 g
(3) 6.54 g (4) 0.00654 g
16. A compound (60 g) on analysis gave C = 24 g, H = 4 g, O = 32 g. Its empirical formula is
(1) C2H4O2 (2) C2H2O2
(3) CH2O2 (4) CH2O
17. 1.0 g of pure calcium carbonate was found to react with 50 ml of dilute HCl for completion of the reaction. The strength of the HCl solution is
(1) 4M (2) 2M (3) 0.4M (4) 0.2M
18. What is the volume of oxygen required for complete combustion of a mixture of 5 cc of CH4 and 5 cc of C2H4?
(1) 25 cc (2) 5 cc (3) 50 cc (4) 10 cc
19. How much of 0.1M of HCl must be added to 0.55 litre of 0.1M NA2CO3 if all of this is to be converted to CO2?
(1) 0.55 litre (2) 1.1 litre
(3) 0.275 litre (4) 100 ml
20. What mole ratio of molecular chlorine (Cl2) to molecular oxygen (O2) would result from the breakup of the compound Cl2O7?
(1) 1:1 (2) 7:2 (3) 1:3.5 (4) 2:4
20. For the reaction A + 2B ___ C, 5 moles of A and 8 moles of B will produce
(1) 5 moles of C (2) 4 moles of C
(3) 8 moles of C (4) 13 moles of C
21. 10 g of carbon burns giving 11.2 litres of CO2 at NTP. After combustion, the amount of unburnt carbon is
(1) 2.5 g (2) 4 g (3) 3 g (4) 1 g
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