EdgineerX

1. The value of Avogadro's number is

A. 6.02 x 10^22 B. 6.02 x 10^23 C. 6.02 x 10^24 D. 3.01 x 10^23 E. 1.66 x 10^-24

2. The molar volume of an ideal gas at standard temperature and pressure is

A. 11.2 dm3 B. 22.414 dm3 C. 24 dm3 D. 1 dm3 E. 44.8 dm3

3. The reactant that is completely consumed first and therefore limits the amount of product is called the

A. excess reactant B. limiting reactant C. catalyst D. intermediate E. spectator species

4. A compound contains 40% carbon, 6.7% hydrogen and 53.3% oxygen by mass. Its empirical formula is

A. CHO B. CH2O C. C2H4O2 D. CH4O E. C2H6O

5. The number of moles in 9.8 g of sulphuric acid is

A. 0.05 B. 0.1 C. 0.2 D. 1.0 E. 0.98

6. The number of molecules in 11.2 dm3 of oxygen gas at STP is

A. 6.02 x 10^23 B. 3.01 x 10^23 C. 1.204 x 10^24 D. 6.02 x 10^22 E. 1.5 x 10^23

7. Isotopes of an element are separated on the basis of

A. chemical reactivity B. difference in mass C. difference in colour D. difference in charge only E. boiling point of the compound

8. A fluted filter paper is used in filtration to

A. reduce the pore size B. increase the surface area available for filtration C. remove coloured impurities D. dry the precipitate E. neutralize the filtrate

9. Which pair of substances can be purified by sublimation?

A. sodium chloride and sugar B. iodine and naphthalene C. glucose and urea D. copper sulphate and alum E. ethanol and water

10. In paper chromatography, the Rf value of a component is always

A. greater than 1 B. equal to 1 C. less than or equal to 1 D. negative E. independent of the solvent

11. Solvent extraction is governed by the

A. law of mass action B. distribution law C. law of definite proportions D. Hess's law E. Raoult's law

12. A good solvent for crystallization should

A. dissolve the solute equally well hot and cold B. dissolve the solute more when hot than when cold C. react with the solute D. have a very high boiling point only E. dissolve the impurities only when cold

13. Boyle's law states that at constant temperature the volume of a given mass of gas is

A. directly proportional to pressure B. inversely proportional to pressure C. independent of pressure D. proportional to the square of pressure E. proportional to temperature

14. Extrapolation of the volume against temperature graph for a gas gives absolute zero at

A. 0 degrees Celsius B. -100 degrees Celsius C. -273.16 degrees Celsius D. -373 degrees Celsius E. 100 degrees Celsius

15. The value of the gas constant R in dm3 atm mol-1 K-1 is

A. 8.314 B. 0.0821 C. 1.987 D. 62.4 E. 0.083

16. According to Graham's law, the rate of diffusion of a gas is

A. proportional to its molar mass B. proportional to the square of its molar mass C. inversely proportional to the square root of its molar mass D. independent of molar mass E. proportional to the square root of its molar mass

17. In the van der Waals equation, the constant b accounts for

A. intermolecular attraction B. the volume occupied by the gas molecules C. the kinetic energy of the molecules D. the temperature correction E. the number of moles

18. A gas cannot be liquefied by pressure alone above its

A. boiling point B. melting point C. critical temperature D. inversion temperature E. transition temperature

19. The average kinetic energy of gas molecules is directly proportional to

A. pressure B. volume C. absolute temperature D. molar mass E. density

20. Dalton's law of partial pressures does not apply to gases that

A. are monatomic B. have different molar masses C. react chemically with each other D. are at high temperature E. are at low pressure

21. The abnormally high boiling point of water compared with hydrogen sulphide is due to

A. its low molar mass B. hydrogen bonding C. London dispersion forces D. its ionic character E. covalent network bonding

22. The boiling point of a liquid at reduced external pressure

A. increases B. decreases C. remains unchanged D. becomes zero E. doubles

23. The coordination number of each ion in a sodium chloride crystal is

A. 4 B. 6 C. 8 D. 12 E. 2

24. The existence of a substance in more than one crystalline form is called

A. isomorphism B. polymorphism C. isotopy D. allotropy in solutions only E. anisotropy

25. Which type of solid has the highest melting point?

A. molecular B. ionic C. metallic D. covalent network E. amorphous

Chemistry