Question

Here is the combustion reaction for octane (C8H18), which is a primary component of gasoline. How many moles of CO2 are emitted into the atmosphere when 11.6 g of C8H18 is burned?

Answer 1

Answer: The amount of $CO_2$ emitted into the atmosphere is 0.808 moles.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$  

For $C_8H_{18}$ :

Given mass of $C_8H_{18}$ = 11.6 g

Molar mass of $C_8H_{18}$ = 114.23 g/mol

Putting values in equation 1, we get:  

$\text{Moles of }C_8H_{18}=\frac{11.6g}{114.23g/mol}=0.101mol$

The chemical equation for the combustion of octane follows:

$2C_8H_{18}+25O_2\rightarrow 16CO_2+18H_2O$

By stoichiometry of the reaction:

2 moles of octane produces 16 moles of carbon dioxide

So, 0.101 moles of octane will produce = $\frac{16}{2}\times 0.101=0.808moles$ of carbon dioxide.

Hence, the amount of $CO_2$ emitted into the atmosphere is 0.808 moles.