Jamb 2015 Chemistry Past Questions And Answers
1
The substance that is used in the steel industry for the removal of carbon, sulphur and phosphorus impurities from pig iron is
- A) oxygen
- B) chlorine
- C) nitrogen
- D) hydrogen
2
Vulcanization involves the removal of
- A) A monomer
- B) The single bond
- C) The double bond
- D) A polymer
3
NH3(g) + HCl(s) → NH4Cl(s) The entropy change in the system above is
- A) positive
- B) zero
- C) negative
- D) indeterminate
4
A difference between chemical and physical change is that in a chemical change
- A) oxygen is consumed
- B) heat is supplied
- C) a reversible process oocurs
- D) a new substance is formed
5
CH3COOC2H5(1) + H2O(1) ⇌ CH 3COOH (aq) + C 2H 5OH (aq)The purpose of H+ in the reaction above is to
- A) increase the yield of products
- B) maintain the solution at a constant PH
- C) increase the rate of the hydrolysis
- D) decrease the rate of the reverse reaction
6
In countries where the temperature falls below 273K, salt is always sprinkled on the icy road in order to
- A) lower the melting point of the ice
- B) increase the density of the ice
- C) make the ice impure
- D) raise the melting point of the ice
7
The IUPAC nomenclature of the compound above is
- A) 2-bromo-3-chlorobutanol
- B) 3-bromo-2-chlorobutanol
- C) 3-chloro-2-bromobutanol
- D) 2-chloro-3-bromobutanol
8
Tartaric acid is used industrially to
- A) make baking powder
- B) make fruit juices
- C) remove rust
- D) dry substance
9
The acid used in electrolysis of water is dilute
- A) HNO3
- B) CH3COOH
- C) H2SO4
- D) HCl
10
Alloys are best prepared by
- A) Electroplating
- B) Arc-welding
- C) Reducing and mixture of their metallic oxide
- D) Cooling a molten mixture of the metals