- 1. 1. In which of the following separation methods does chemical reaction occur?
A) Precipitation
B) Distillation
C) Chromatography
D) Sublimation
- 2. 2. The purity of a solid sample can best be determined by its :
A) Solubility
B) Conductivity
C) Boiling points
D) Melting point
- 3. 3. The constituent of lead pigment can be separated by:
A) Fractional crystallisation
B) Chromatography
C) Fractional distillation
D) Filtration
- 4. 4. Which of the following properties is not employed in the separation of a mixture?
A) Densities
B) Boiling points
C) Solubility
D) Molar masses
- 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) Filtration
D) Fractional crystallisation
- 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) Sublimation
C) Crystallisation
D) Evaporation
- 7. 7. Fractional distillation is used to separate:
A) An insoluble substance from a soluble substance
B) Gaseous, liquid or solid impurities from a mixture
C) Substances which differ in their solubilities in a solvent
D) Liquids with different boiling points
- 8. 8. A mixture of kerosene and water can be separated by:
A) Distillation
B) Sublimation
C) Separating funnel
D) Crystallisation
- 9. 9. What is the mass number of an element if its atom contains 10 protons, 10 electrons, and 12 neutrons?
A) 20
B) 10
C) 32
D) 22
- 10. 10. The electronic configuration of an atom is 2,8,8,2. The atomic number of the element is, therefore ----------:
A) 18
B) Z15
C) 20
D) 10
- 11. 11. What is the percentage by mass of sodium in sodium hydroxide? (Na = 23, O = 16, H = 1)
A) 73.0%
B) 40.4%
C) 57.5%
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) 21.33%
B) 28.07%
C) 42.66%
D) 14.71%
- 13. 13. How many electrons are in the ion F, If 19 F has neutron of 8?
A) 11
B) 27
C) 8
D) 9
- 14. 14. Calculate the formula mass of tri lead tetraoxide Pb3O4 (Pb= 207, O = 16)
A) 865
B) 621
C) 685
D) 586
- 15. 15. Calculate the formula mass of tetraoxosulphate (VI) acid 3H2SO4 (S= 32, H = 1, O = 16)
A) 294
B) 240
C) 64
D) 102
- 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 × 1032
B) 6.02 × 10-23
C) 6.02 × 10-32
D) 6.02 × 1023
- 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) Argon
B) Chlorine
C) Sulphur
D) Potassium
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