Chemistry Past Questions And Answers
31
There is a large temperature interval between the melting point and the boiling point of a metal because
- A) metals have very high melting points
- B) metal conduct heat very rapidly
- C) melting does not break the metallic bond but boiling does
- D) the crystal lattice of metals is easily broken
32
Copper and silver metals are commonly use as coin because they are
- A. easily reduced
- B. not easily reduced
- C. easily oxidized
- D. not easily oxidized
33
What is the solubility of a salt if 0.4g of it is obtained on evaporating 200cm3 of its saturated solution to dryness?
- A. 0.08gdm−3
- B. 2.00gdm−3
- C. 8.00gdm−3
- D. 80.00gdm−3
34
Using the metal activity series, the metal that can liberate hydrogen gas from steam is?
- A. iron
- B. copper
- C. tin
- D. lead
35
If 1 mole of sodium contains 6 x 1023 atoms, how many atoms are contained in 0.6 g of sodium? [Na = 23]
- A. 1.56 x 1023
- B. 1.56 x 1022
- C. 3.6 x 1023
- D. 3.6 x 1022
36
Which of the following substances is a peroxide?
- A. Na2O2
- B. CuO
- C. PbO4
- D. Fe2O
37
The separation technique that is suitable for separating iodine from tetrachloromethane is
- A. solvent extraction
- B. decantation
- C. fractional distillation
- D. filtration
38
Water gas is a mature of
- A Co2 and H2
- B. CO and H2O
- C. Co and H2
- Co2 and Co
39
According to Charles' law, the volume of a gas becomes zero at
- A) 0°C
- B) -100°C
- C) -273°C
- D) -373°C
40
Solubility is practically applied in
- A. Fractional distillation
- B. The determination of pH
- C. The determination of saturation in hydrocarbons
- D. Solvent extraction