# When the following equation is balanced in standard form, what is the coefficient in front of CO2(g)? C2H6(g) + O2(g) ® CO2(g) + H2O(l) A)1 B)2 C)3 D)4 E)5

Feb 24, 2015

The balanced equation is:

${C}_{2} {H}_{6 \left(g\right)} + 3 \frac{1}{2} {O}_{2 \left(g\right)} \rightarrow 2 C {O}_{2 \left(g\right)} + 3 {H}_{2} {O}_{\left(l\right)}$

In this case the coefficient is 2.

I could double everything then it would be 4.

I guess that is what you mean by "standard form"?

Feb 24, 2015

The balanced chemical equation for the combustion of ethane, or ${C}_{2} {H}_{6}$, looks like this

$2 {C}_{2} {H}_{6 \left(g\right)} + 7 {O}_{2 \left(g\right)} \to 4 C {O}_{2 \left(g\right)} + 6 {H}_{2} {O}_{\left(l\right)}$

This means that the coefficient in front of $C {O}_{2}$ will be 4 - option D.

SIDE NOTE You'll sometimes see this written with fractional coefficients, but the standard form equation has coefficients that are integers for all species involved.

${C}_{2} {H}_{6} + 3.5 {O}_{2} \to 2 C {O}_{2} + 3 {H}_{2} O$ $\to$ don't use this version when asked for standard form.