Chemistry Past Questions And Answers
Thermal cracking of alkanes usually
- A. is an exothermic process
- B. produces only small alkanes
- C. involves decomposition
- D. requires hydrogen
Which of the following statements is not true of tin? it
- A. is a p-block element
- B. is extracted from cassiterite SnO 2
- C. is used for protecting iron containers from corrosion
- D. combines with copper to form the alloy brass
What is the concentration of a solution which contains 0.28g of potassium hydroxide in 100 cm-3 of solution [KOH = 56]
- A. 0.01 mol dm-3
- B. 0.05 mol dm-3
- C. 0.10 mol dm-3
- D. 0.50 mol dm-3
The mass of 800cm3 of a gas X at s.t.p. is 1.0g. What is the molar mass of X? [1 mole of a gas at s.t.p occupies 22.4dm3]
- A. 18.0gmol-1
- B. 22.4gmol-1
- C. 28.0gmol-1
- D. 36.0gmol-1
Stainless steel is used for making
- A) magnets
- B) tools
- C) coins and medals
- D) moving parts of clocks
State the atoms represented as shown in the diagram below:
(a) State the relationship between the two atoms.
(b) What is the difference between them?
(c) Give two examples of elements which exhibit the phenomenon illustrated above.
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) From the equation above, the mass of magnesium required to react with 250cm3 of 0.5M HCl is [Mg = 24]
- A. 0.3g
- B. 1.5g
- C. 2.4g
- D. 3.0g
Which of the following oxide causes acid rain?
- A. CO
- B. NO
- C. H2O2
- D. NO2
A pure solid usually melts _______
- A).over a wide range of temperature
- B) over a narrow range of temperature
- C) at a lower temperature than the impure one
- D) at the same temperature as the impure one
What is the volume of oxygen required to bum completely 45cm3 of methane at s.t.p?
- A) 135.0cm3
- B) 180.0cm3
- C) 45.0cm3
- D) 90.0cm3