- 1. 1. In which of the following separation methods does chemical reaction occurs?
A) Chromatography B) Distillation C) Sublimation D) Precipitation
- 2. 2. The purity of a solid sample can best be determined by its :
A) Melting point B) Conductivity C) Boiling points D) Solubility
- 3. 3. The constituent of lead pigment can be separated by:
A) Fractional distillation B) Fractional crystallisation C) Chromatography D) Filtration
- 4. 4. Which of the following properties is not employed in the separation of a mixture?
A) Boiling points B) Molar masses C) Densities D) Solubility
- 5. 5. Ethanol is a product of fermentation of simple sugars. Which method is used to separate ethanol from the other products?
A) Fractional crystallisation B) Fractional distillation C) Filtration D) Boiling off the ethanol
- 6. 6. When a solid substance changes directly to a gas on heating without passing through the liquid state, the substance is said to have undergone:
A) Melting B) Crystallisation C) Sublimation D) Evaporation
- 7. 7. Fractional distillation is used to separate:
A) Liquids with different boiling points B) Gaseous, liquid or solid impurities from a mixture C) An insoluble substance from a soluble substance D) Substances which differ in their solubilities in a solvent
- 8. 8. A mixture of kerosene and water can be separated by:
A) Distillation B) Crystallisation C) Sublimation D) Separating funnel
- 9. 9. What is the mass number of an element if its atom contains 10 protons, 10 electrons, and 12 neutrons?
A) 10 B) 32 C) 22 D) 20
- 10. 10. The electronic configuration of an atom is 2,8,8,2. The atomic number of the element is, therefore ----------:
A) 18 B) 20 C) Z15 D) 10
- 11. 11. What is the percentage by mass of sodium in sodium hydroxide? (Na = 23, O = 16, H = 1)
A) 57.5% B) 40.4% C) 73.0% D) 42.5%
- 12. 12. What is the percentage by mass of sulphur in aluminium tetraoxosulphate (VI), Al2(SO4)_3. ( Al = 27, S = 32, O = 16)
A) 14.71% B) 21.33% C) 42.66% D) 28.07%
- 13. 13. How many electrons are in the ion F, If 19 F has neutron of 8?
A) 8 B) 27 C) 9 D) 11
- 14. 14. Calculate the formula mass of tri lead tetraoxide Pb3O4 (Pb= 207, O = 16)
A) 621 B) 586 C) 865 D) 685
- 15. 15. Calculate the formula mass of tetraoxosulphate (VI) acid H2SO4 (S= 32, H = 1, O = 16)
A) 64 B) 40 C) 98 D) 102
- 16. 16. What is the molecular mass of calcium trioxonitrate (V) Ca (NO3)_2 (Ca = 40, N = 14, O = 16)
A) 146 B) 104 C) 160 D) 164
- 17. 17. One of the following is the avogadro's constant:
A) 6.02 × 10-23 B) 6.02 × 1023 C) 6.02 × 1032 D) 6.02 × 10-32
- 18. 18. The relative atomic mass of any element in grams contains -------- mole of atom
A) 4 B) 2 C) 1 D) 3
- 19. 19. The sum of the relative atomic masses of all the atoms in one molecule of the substance is referred to as ----------
A) Relative atomic mass B) Relative abundance C) Relative molecular mass D) Relative avogadro's abundance
- 20. 20. The electronic configuration of an atom is: 2, 8, 7. What element is it?
A) Chlorine B) Sulphur C) Potassium D) Argon
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