CHEM. MC 3

Question 1:
In an exothermic reaction,
(1) there is a release of energy to the surrounding.
(2) the heat of reaction H is negative.
(3) the reacting species react spontaneously.
A. (1) only
B. (2) only
C. (1) and (2) only
D. (2) and (3) only
Question 2:
Which of the following statements is / are true for an endothermic reaction?
(1) The reaction absorbs heat from the surroundings.
(2) The temperature of the reaction decreases as the reaction proceeds.
(3) The energy of the products is higher than that of the reactants.
A. (1) only
B. (1) and (2) only
C. (2) and (3) only
D. All of them
Question 3:
Which of the following statements about the reaction shown below is incorrect?
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) H is negative
A. Magnesium is being oxidized in the reaction.
B. One mole of magnesium produces one mole of hydrogen in the reaction.
C. The total energy content of the products is greater than that of the reactants.
D. The reaction shows that magnesium is above hydrogen in the reactivity series.
Question 4:
Consider the following equation:
2Al(s) + 1½O2(g) → Al2O3(s) H = -2060kJ
Which of the following statements concerning the above equation is correct?
A. There is heat gain from the surroundings in the reaction.
B. The heat content of the reactants is lower than that of the product.
C. The final temperature rises above the initial temperature.
D. 2060 kJ of heat energy is given out when 1 mole of aluminium reacts.
2
Question 5:
The equation for the reaction of calcium carbonate with hydrochloric acid is
CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g)
From the equation alone, which of the following aspects the reaction can be
deduced?
A. the percentage yield of the products
B. the energy change in the reaction
C. the rate at which hydrochloric acid reacts with calcium carbonate
D. the mass of calcium carbonate required to react with a molar quantity of
hydrochloric acid