- 1. 1. In which of the following separation methods does chemical reaction occur?
A) Distillation
B) Chromatography
C) Precipitation
D) Sublimation
- 2. 2. The purity of a solid sample can best be determined by its :
A) Conductivity
B) Melting point
C) Boiling points
D) Solubility
- 3. 3. The constituent of lead pigment can be separated by:
A) Chromatography
B) Filtration
C) Fractional distillation
D) Fractional crystallisation
- 4. 4. Which of the following properties is not employed in the separation of a mixture?
A) Molar masses
B) Densities
C) Boiling points
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) Filtration
C) Boiling off the ethanol
D) Fractional distillation
- 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) Crystallisation
B) Sublimation
C) Evaporation
D) Melting
- 7. 7. Fractional distillation is used to separate:
A) Liquids with different boiling points
B) Gaseous, liquid or solid impurities from a mixture
C) Substances which differ in their solubilities in a solvent
D) An insoluble substance from a soluble substance
- 8. 8. A mixture of kerosene and water can be separated by:
A) Separating funnel
B) Sublimation
C) Crystallisation
D) Distillation
- 9. 9. What is the mass number of an element if its atom contains 10 protons, 10 electrons, and 12 neutrons?
A) 32
B) 10
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) Z15
B) 18
C) 10
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) 57.5%
C) 40.4%
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) 28.07%
B) 21.33%
C) 14.71%
D) 42.66%
- 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) 865
B) 586
C) 685
D) 621
- 15. 15. Calculate the formula mass of tetraoxosulphate (VI) acid 3H2SO4 (S= 32, H = 1, O = 16)
A) 64
B) 240
C) 102
D) 294
- 16. 16. What is the molecular mass of calcium trioxonitrate (V) 2Ca (NO3)_2 (Ca = 40, N = 14, O = 16)
A) 328
B) 160
C) 164
D) 346
- 17. 17. One of the following is the Avogadro's constant:
A) 6.02 × 10-32
B) 6.02 × 1023
C) 6.02 × 1032
D) 6.02 × 10-23
- 18. 18. The relative atomic mass of any element in grams contains -------- mole of atom
A) 2
B) 3
C) 4
D) 1
- 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 abundance
B) Relative atomic mass
C) Relative molecular mass
D) Relative avogadro's abundance
- 20. 20. The electronic configuration of an atom is: 2, 8, 8,1. What element is it?
A) Chlorine
B) Sulphur
C) Argon
D) Potassium
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