Chapter 9.6, Problem 39PP

(a)

Interpretation Introduction

Interpretation : The kilojoules of heat released when 125 g of ${\text{Cl}}_{\text{2}}$ reacts with silicon.

Concept Introduction : A chemical reaction can be two types; endothermic and exothermic based on energy change during the reaction. An exothermic reaction occurs with release of energy that decreases the energy level of product compare to reactant whereas endothermic reactions occur with absorption of energy that increases the energy level of product molecule than reactant molecules.

(b)

Interpretation Introduction

Interpretation : The kilojoules of heat absorbed when 278 g of ${\text{PCl}}_{\text{5}}$ reacts should be calculated.

Concept Introduction : A chemical reaction can be two types; endothermic and exothermic based on energy change during the reaction. An exothermic reaction occurs with release of energy that decreases the energy level of product compare to reactant whereas endothermic reactions occur with absorption of energy that increases the energy level of product molecule than reactant molecules.