Q. 7.107 - An Introduction to General, Organic, and Biological Chemistry

Question

The equation for the formation of silicon tetrachloride from silicon and chlorine is ($7.9$)

data-custom-editor="chemistry" $\mathrm{Si}\left(\mathrm{s}\right) + 2{\mathrm{Cl}}_2\left(\mathrm{g}\right) \to {\mathrm{SiCl}}_4\left(\mathrm{g}\right) + 157 \mathrm{kcal}$

a. Is the formation of data-custom-editor="chemistry" ${\mathrm{SiCl}}_4$, an endothermic or exothermic reaction?

b. Is the energy of the product higher or lower than the energy of the reactants?

Step-by-Step Solution

Answer

(a) Formation of ${\mathrm{SiCl}}_4$ is an exothermic reaction

(b) The energy of product is lower than energy of the reactants 

Part (a) Step 1: Given information

We need to find that whether the formation of ${\mathrm{SiCl}}_4$ is exothermic or endothermic

Part (a) Step 2: Explanation

We know that

A reaction in which energy is released is called an exothermic reaction

And in given $157 kcal$ of energy is released

Therefore, Formation of ${\mathrm{SiCl}}_4$ is an exothermic reaction 

Part (b) Step 1: Given information

We need to find the energy of the product higher or lower than the energy of the reactants 

Part (b) Step 2: Explanation

We know that

The total energy of reactants is equal to the total energy of products in a reaction

And as the energy on the product side is released separately

Therefore, the energy of the product is lower than the energy of the reactants