The following are s-block elements except
- A. lithium
- B. magnesium
- C. potassium
- D. calcium
- E. aluminium
Given that for the reaction. N2(g) + 3H2(g) ⇌ 2NH3(g) ∆H = -92kJ. What is the enthalpy of formation of ammonia from its elements?
- A. -46KJ mol -1
- B. -184KJmol -1
- C. -92KJmol -1
- D. 184KJmol -1
- E. +46KJmol -1
If sulphur is dissolved in carbon (IV) sulphide and the solution is allowed to evaporate, the allotrope of sulphur formed is
- A. plastic sulphur
- B. amorphous sulphur
- C. rhombic sulphur
- D. monoclinc sulphur
- E. colloidal sulphur
If sulphur is dissolved in carbon (IV) sulphide and the solution allowed to evaporate the allotrope of sulphur formed is
- A. plastic sulphur
- B. amorphous sulphur
- C. rhombic sulphur
- D. monoclinc sulphur
- E. colloidal sulphur
Given that 1 mole of carbon -12 weighs 12.0g, how many atoms are there in 24.0g magnesium? (C = 12, Mg = 24, NA = 6.02 x 10 23mol-1)
- A. 1/2 x 6.02 x 10 23
- B. 1 x 6.02 x10 23
- C. 2 x 6.02 x 10 23
- D. 3x 6.02 x 10 23
- E. 4x 6.02 x 10 23
Which of the following is used extensively in manufacturing photographic chemicals?
- A. Aluminium chloride
- B. Zinc chloride
- C. Silver chloride
- D. Mercury (ll) chloride
- E. lron (ll) chloride
Given the following half-cell reaction; 2Cl(aq) → CI2(g) + 2e, how many mole of electrons will be required to produce 1.12dm3 of chlorine gas at s.t.p? (Molar volume of a gas at s.t.p. = 22.4dm 3)
- A. 1.00
- B. 0.40
- C. 0.20
- D. 0.10
- E. 0.01
Octane number is highest in petrol containing a high proportion of
- A. heptane
- B. octane
- C. 2-methylpentane
- D. 2, 4-dimethylpentane
- E. 2,2,4-trimethylpentane
The rate of the hydrogen in the reaction Zn(s) + 2HCI (aq) → ZnCI 2(g) + H 2(aq) + H 2(g) can be increased by
- A. using Zinc powder instead of Zinc granules
- B. using dilute instead of concentrated hydrochloric acid
- C. cooling the container in which the mixture is placed
- D. using an alloy of zinc instead of pure zinc
- E. using hydrogen chloride gas instead of hydrochloric acid solution
Why is potassium fluoride added to the electrolyte in the extraction of sodium from fused sodium chloride?
- A. Pure sodium chloride does not conduct electricity
- B. Potassium fluoride prevents the sodium produced from attacking the electrodes
- C. Potassium fluride increases conductivity
- D. Potassium fluride reduces the temperature at which sodium chloride fuses
- E. the potassium fluride acts as a catalyst
Locally produced soap in which wood ash is used as the base is usually soft because the wood ash contains a lot of
- A. sodium ions
- B. potassium ions
- C. lithium ions
- D. calcium ions
- E. magnesium ions
Copper can best be purified by
- A. roasting the impure copper in a blast furnace
- B. heating the oxide with coke
- C. electrolyzing a copper (ll) salt solution using the impure copper as the anode
- D. converting the impure copper to a trioxonitrate (V)
- E. washing the impure copper with sodium hydroxide solution
Which of the following carbohydrates does NOT usually occur in the crystalline form?
- A. Fructose
- B. Glucose
- C. Sucrose
- D. Maltose
- E. Cellulose
When an element can exist in two or more forms in the same physical state, the element is said to exhibit
- A. isotopy
- B. isomerism
- C. allotropy
- D. hygroscopy
- E. sublimation
Given that for the reaction KOH (aq) + HCI(aq) → KCI(aq) + H2O(L) H = – 54 Kj mol-1. What is the quantity of heat involved in the reaction?2NaOH(aq) + H2SO 4(aq) → Na2SO4(aq) + 2H 2O(l)?
- A. - 108Kj
- B. -54 kj
- C. -27 kj
- D. +27 kj
- E. +54 kj
Which of the following gases will bleach moist litmus paper?
- A. CI2
- B. CO2
- C. SO2
- D. HCI2
- E. N2 O
How many carbon atoms are there in a benzene ring?
- A. 4
- B. 5
- C. 6
- D. 7
- E. 8
If 200cm 3 of a gas at s.t.p. has a mass of 0.268g, what is its molar mass? (Molar volume of a gas at s.t.p. = 22.4 dm3)
- A. 300g
- B. 200g
- C. 150g
- D. 30g
- E. 15g
The following are miscible with water except
- A. ethylethanoate
- B. methanol
- C. ethanoic acid
- D. methanoic acid
- E. ethanol
The most suitable method to use when separating an insoluble solid from a liquid is
- A. evaporation
- B. filtration
- C. magnetization
- D. sublimation
- E. distillation
Which of the following hydrocarbons is not likely to be present in petrol?
- A. C14H30
- B. C10H22
- C. C9H20
- D. C7H16
- E. C5H12