Question

How many moles of O2 are needed to react with 2.55 mol of C2H2?

Answer 1

Answer: 6.38 moles of $O_2$ are needed to react with 2.55 mol of $C_2H_2$

Explanation:

The balanced chemical reaction for the combustion of ethyne is:

$2C_2H_2+5O_2\rightarrow 4CO_2+2H_2O$

According to stoichiometry:

2 moles of $C_2H_2$ require = 5 moles of $O_2$

Thus 2.55 mol of $C_2H_2$ require = $\frac{5}{2}\times 2.55=6.38$ moles of $O_2$

Thus 6.38 moles of $O_2$ are needed to react with 2.55 mol of $C_2H_2$