- 1. 1. In which of the following separation methods does chemical reaction occurs?
A) Precipitation
B) Chromatography
C) Sublimation
D) Distillation
- 2. 2. The purity of a solid sample can best be determined by its :
A) Boiling points
B) Conductivity
C) Melting point
D) Solubility
- 3. 3. The constituent of lead pigment can be separated by:
A) Filtration
B) Fractional crystallisation
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) Fractional crystallisation
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) Sublimation
C) Evaporation
D) Crystallisation
- 7. 7. Fractional distillation is used to separate:
A) Liquids with different boiling points
B) An insoluble substance from a soluble substance
C) Gaseous, liquid or solid impurities from a mixture
D) Substances which differ in their solubilities in a solvent
- 8. 8. A mixture of kerosene and water can be separated by:
A) Crystallisation
B) Separating funnel
C) Sublimation
D) Distillation
- 9. 9. What is the mass number of an element if its atom contains 10 protons, 10 electrons, and 12 neutrons?
A) 22
B) 10
C) 32
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) 10
D) Z15
- 11. 11. What is the percentage by mass of sodium in sodium hydroxide? (Na = 23, O = 16, H = 1)
A) 40.4%
B) 73.0%
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) 9
B) 27
C) 11
D) 8
- 14. 14. Calculate the formula mass of tri lead tetraoxide Pb3O4 (Pb= 207, O = 16)
A) 586
B) 685
C) 621
D) 865
- 15. 15. Calculate the formula mass of tetraoxosulphate (VI) acid H2SO4 (S= 32, H = 1, O = 16)
A) 102
B) 64
C) 98
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) 164
C) 160
D) 146
- 17. 17. One of the following is the avogadro's constant:
A) 6.02 × 10-23
B) 6.02 × 1032
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) 4
C) 3
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 molecular mass
C) Relative atomic mass
D) Relative avogadro's abundance
- 20. 20. The electronic configuration of an atom is: 2, 8, 7. What element is it?
A) Potassium
B) Chlorine
C) Sulphur
D) Argon
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