Chemistry Past Questions and Answers

What weight of sodium hydroxide is required to make 500 cm3 of 0.2 M solution? (Na = 23, O = 16, H = 1)

A 40 g
B 20 g
C 10 g
D 4 g
E 2 g

Question 292:

Which of the following combinations of conditions may increase the rate of a chemical reaction?

A Decrease in temperature, increase in concentration of the reactants
B Increase in temperature, addition of a catalyst, decrease in the surface area of the reactants
C Increase in temperature, increase in concentration, addition of a catalyst and increase in the surface area of the reactants
D Decrease in temperature concentration and surface area of the reactants
E Additionof a catalyst and in the absence of light

Question 293:

Which of the following is NOT a redox reaction?

A 2HNO2 + 2HI â†’ 2H2O + 2NO + I2
B Zn + H2SO4 → ZnSO4 + H2
C Ca(HCO3)2 â†’ CaCO3 + H2O + CO2
D 4FeO + O2 â†’ 2Fe2O3
E 2Na + Cl2 â†’ 2NaCl

Question 294:

0.16g of methane when burnt raises the temperature of 100g of water by 40°C. What is the of combustion of methane when if the heat capacity of water is 4.2 Jg-1°C-1? (CH4 = 16)

A 1,160 kJ mol-1
B 1,180 kJ mol-1
C 1,560 kJ mol-1
D 1,600kJ mol-1
E 1,680 kJ mol-1

Question 295:

Which of the following processes NOT lead to a chemical change?

A Strirring iron in sulphur (IV) acid
B Stirring sodium carbonate in water
C Stirring glucose in concentrated sulphur (IV) acid
D Mixing sulphur (IV) acid with potassium carbonate
E Titrating an acid against base