Chapter 14, Problem 119A

(a)

Interpretation Introduction

Interpretation: To determine the type of reaction when calcium is made to react with water forming calcium hydroxide and Hydrogen gas.

Concept Introduction: Combination reactions are those reactions in which two reactants combine to form a single product. Some reactions between metals and halogens in the reactions are an example of combination reactions and also some natural oxidation reactions are also combination reactions.

Answer to Problem 119A

It is a type of combination reaction.

Explanation of Solution

In the given combination reaction calcium is made to react with water to form the appropriate product. 1 mole of Calcium is made to react with 2 moles of water which result in the formation of one mole of calcium hydroxide. In this calcium is combined with water to form calcium hydroxide. Hence, it is a combination reaction.

(b)

Interpretation Introduction

Interpretation: To determine the type of reaction that helps in producing mercury and oxygen from Mercury (II) oxide.

Concept introduction: Thermal decomposition reaction is a decomposition reaction in which a single substance breaks down to form two or more simpler substances. The formation of two or more simpler substances is done in the presence of heat and these types of reactions are endothermic reactions.

Answer to Problem 119A

The reaction is a thermal decomposition reaction.

Explanation of Solution

When mercury (II) oxide is heated, it results in the formation of mercury and oxygen. The mercury that is formed will be in the liquid form and the oxygen that is formed will be a gas. This reaction is an endothermic reaction.