Chapter 6, Problem 6.92P

(a)

Interpretation Introduction

Interpretation:

$\Delta H_{\text{rxn}}^{°}$ for the gas-phase reaction of ethylene oxide $\left(\text{EO}\right)$ is to be calculated.

Concept introduction:

The standard enthalpy of reaction is calculated by the summation of standard enthalpy of formation of the product minus the summation of standard enthalpy of formation of product at the standard conditions. The formula to calculate the standard enthalpy of reaction $\left(\Delta H_{\text{rxn}}^{°}\right)$ is as follows:

$\Delta H_{\text{rxn}}^{°}=\sum m\Delta H_{\text{f (products)}}^{°}-\sum m\Delta H_{\text{f (reactants)}}^{°}$

Here, m and n are the stoichiometric coefficients of reactants and product in the balanced chemical equation.

(b)

Interpretation Introduction

Interpretation:

The final temperature if the average specific heat capacity of the products is $2.5\text{ J/g}\cdot \text{°C}$ is to be determined.

Concept introduction:

Heat capacity $\left(C\right)$ of a material is the quantity to measure the heat needed to raise the temperature of a substance by $1\text{K}$. The formula to calculate heat required is as follows:

$q=\left(C\right)\left(\Delta T\right)$ (5)

Here,

$\Delta T$ is the temperature difference.

$q$ is the heat released or absorbed.

$C$ is the heat capacity of the substance.

Specific heat capacity $\left(c\right)$ of a substance is the quantity to measure the heat needed to raise the temperature of $1\text{g}$ of a substance by $1\text{K}$. The formula to calculate heat required is as follows:

$q=\left(\text{mass}\right)\left(c\right)\left(\Delta T\right)$ (6)

Here,

$\Delta T$ is the temperature difference.

$q$ is the heat released or absorbed.

$c$ is the specific heat capacity of the substance.