Question

Balance the following combustion reaction in order to answer the following questions. Use lowest whole-number coefficients.

C2H4 + O2 ---> CO2 + H20

You are given 7.5 moles of O2 to react with 1.80 × 102 g C2H4. Upon completion of the reaction, will there be any remaining C2H4?

Answer 1

Answer on Question #40484, Chemistry, Other

Question

Balance the following combustion reaction in order to answer the following questions. Use lowest whole-number coefficients.

$$\mathrm{C_2H_4} + \mathrm{O_2} \rightarrow \mathrm{CO_2} + \mathrm{H_2O}$$

You are given 7.5 moles of $\mathrm{O_2}$ to react with $1.80 \times 10^{2} \, \mathrm{g} \, \mathrm{C_2H_4}$. Upon completion of the reaction, will there be any remaining $\mathrm{C_2H_4}$?

Answer

$$\mathrm{C_2H_4} + 3\mathrm{O_2} \rightarrow 2\mathrm{CO_2} + 2\mathrm{H_2O}$$

Stoichiometric ratio: $n(\mathrm{O_2}) / n(\mathrm{C_2H_4}) = 3$.

**Quantity of $\mathrm{C_2H_4}$:**

$$\mathrm{M}(\mathrm{C_2H_4}) = 28 \, \mathrm{g/mol}$$ $$n(\mathrm{C_2H_4}) = 1.80 \times 10^{2} \, \mathrm{g} / 28 \, \mathrm{g/mol} = 6.42 \, \mathrm{mol}$$

**Given ratio:**

$$n(\mathrm{O_2}) / n(\mathrm{C_2H_4}) = 7.5 / 6.42 = 1.17.$$

Given ratio is lesser than the stoichiometric ratio, hence $\mathrm{C_2H_4}$ is in excess (there is not enough $\mathrm{O_2}$ to combust all the $\mathrm{C_2H_4}$) and will remain upon completion of the reaction.