Chapter 7, Problem 9A

(a)

Interpretation Introduction

Interpretation: The physical state of each reactant and product needs to be identified.

Concept Introduction: In a chemical reaction, reactant entities are given on left-hand side and product entities on right-hand side.

Answer to Problem 9A

  $2{\text{H}}_{\text{2}}(g)+{\text{O}}_{\text{2}}(g)\to {\text{2H}}_{\text{2}}\text{O}(l)$

In a chemical reaction, reactants hydrogen and oxygen are in a gaseous state and product water is in a liquid state.

Explanation of Solution

Hydrogen in gases state reacts with oxygen gas and produce water in liquid form. A physical state of reactants and products is represented in brackets with the symbol of reactants and products.

(b)

Interpretation Introduction

Interpretation: The chemistry behind the reaction needs to be explained.

Concept Introduction: In a chemical reaction, reactant entities are given on left-hand side and product entities on right-hand side.

Answer to Problem 9A

The given reaction is as follows:

  $2{\text{H}}_{\text{2}}(g)+{\text{O}}_{\text{2}}(g)\to {\text{2H}}_{\text{2}}\text{O}(l)$

During this chemical reaction, Hydrogen gas burns in the presence of oxygen gas, a new substance liquid water forms. The covalent bonds within Hydrogen and oxygen molecules break and new covalent bonds are formed between the oxygen atom and hydrogen atoms.

Explanation of Solution

Two atoms of oxygen in diatomic form react with four hydrogen atoms means two molecules of hydrogen and form two water molecules.