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