Question

Carbon and oxygen react to produce carbon dioxide. What is the weight of oxygen required to convert $1.5g$ of carbon to carbon dioxide?

• A. $2g$
• B. $6g$
• C. $1g$
• D. $4g$

Answer 1

The correct option is D $4g$

$C+O_2\to C{O}_2$

The atomic mass of C is 12 g/mol. The number of moles of C

$=\frac{1.5g}{12g/mol}=0.125$ mol.

1 mole of C reacts with 1 mole of $O_2$.

0.125 moles of C will react with 0.125 moles of $O_2$.

The molecular weight of $O_2$ is 32 g/mol.
Mass of $O_2$ $=0.125$ mol $\times 32$ g/mol $=4$ g.