- 1. 1. In which of the following separation methods does chemical reaction occurs?
A) Distillation B) Sublimation C) Chromatography D) Precipitation
- 2. 2. The purity of a solid sample can best be determined by its :
A) Conductivity B) Solubility C) Boiling points D) Melting point
- 3. 3. The constituent of lead pigment can be separated by:
A) Fractional crystallisation B) Filtration C) Chromatography D) Fractional distillation
- 4. 4. Which of the following properties is not employed in the separation of a mixture?
A) Molar masses B) Solubility C) Boiling points D) Densities
- 5. 5. Ethanol is a product of fermentation of simple sugars. Which method is used to separate ethanol from the other products?
A) Fractional distillation B) Boiling off the ethanol C) Fractional crystallisation D) Filtration
- 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) Evaporation B) Sublimation C) Melting D) Crystallisation
- 7. 7. Fractional distillation is used to separate:
A) An insoluble substance from a soluble substance B) Substances which differ in their solubilities in a solvent C) Gaseous, liquid or solid impurities from a mixture D) Liquids with different boiling points
- 8. 8. A mixture of kerosene and water can be separated by:
A) Crystallisation B) Distillation C) Separating funnel D) Sublimation
- 9. 9. What is the mass number of an element if its atom contains 10 protons, 10 electrons, and 12 neutrons?
A) 20 B) 32 C) 10 D) 22
- 10. 10. The electronic configuration of an atom is 2,8,8,2. The atomic number of the element is, therefore ----------:
A) 10 B) 18 C) Z15 D) 20
- 11. 11. What is the percentage by mass of sodium in sodium hydroxide? (Na = 23, O = 16, H = 1)
A) 73.0% B) 42.5% C) 40.4% D) 57.5%
- 12. 12. What is the percentage by mass of sulphur in aluminium tetraoxosulphate (VI), Al2(SO4)_3. ( Al = 27, S = 32, O = 16)
A) 21.33% B) 14.71% C) 28.07% D) 42.66%
- 13. 13. How many electrons are in the ion F, If 19 F has neutron of 8?
A) 9 B) 8 C) 27 D) 11
- 14. 14. Calculate the formula mass of tri lead tetraoxide Pb3O4 (Pb= 207, O = 16)
A) 586 B) 621 C) 685 D) 865
- 15. 15. Calculate the formula mass of tetraoxosulphate (VI) acid H2SO4 (S= 32, H = 1, O = 16)
A) 98 B) 102 C) 64 D) 40
- 16. 16. What is the molecular mass of calcium trioxonitrate (V) Ca (NO3)_2 (Ca = 40, N = 14, O = 16)
A) 104 B) 160 C) 146 D) 164
- 17. 17. One of the following is the avogadro's constant:
A) 6.02 × 1023 B) 6.02 × 10-23 C) 6.02 × 10-32 D) 6.02 × 1032
- 18. 18. The relative atomic mass of any element in grams contains -------- mole of atom
A) 2 B) 4 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 molecular mass B) Relative atomic mass C) Relative avogadro's abundance D) Relative abundance
- 20. 20. The electronic configuration of an atom is: 2, 8, 7. What element is it?
A) Chlorine B) Argon C) Potassium D) Sulphur
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