Question

If 8 moles of the hydrocarbon in the equation referenced above fully reacts howmany moles of oxygen would be needed?2C8H18 +25O2 = 18H2O + 16CO2

Answer 1

100 moles of oxygen

Explanations:

Given the chemical reaction between the hydrocarbon compound and oxygen expressed as:

`2C_8H_(18)+25O_2\rightarrow18H_2O+16CO_2`

Based on stoichiometry, you can see that 2 moles of the hydrocarbon compound react with 25 moles of oxygen. Therefore if 8 moles of the hydrocarbon in the equation fully react, the number of moles of oxygen needed will be expressed as:

`\text{moles of O}_2=\frac{8\cancel{molesofC_8H_{\mleft\{18\mright\}}}}{2\cancel{molesofC_8H_(18)}}*25molesofO_2`

The number of moles of oxygen needed will be simplified further as:

`\begin{gathered} \text{moles of O}_2=\frac{\cancel{8}^4}{\cancel{2}_{}}*25molesofO_2 \\ \text{moles of O}_2=4*25molesofO_2 \\ \text{moles of O}_2=100\text{moles} \end{gathered}`

This shows that if 8 moles of the hydrocarbon in the equation fully react, 100 moles of oxygen would be needed.