Question

1 gm butane is burnt with excess of O2 to form co2. The approximate mass of CO2 produced is 1) 1 gm 2) 2gm 3) 3 gm 4) 4 gm

Answer 1

Answer: 3) 3 gm

Explanation:

Combustion is a chemical reaction in which a is reacted with oxygen to form carbon dioxide and water.

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number $6.023\times 10^{23}$ of particles.

To calculate the moles, we use the equation:

$\text{Number of moles of butane}=\frac{\text{Given mass}}{\text {Molar mass}}=\frac{1.0g}{58g/mol}=0.0172moles$

$2C_4H_{10}+13O_2\rightarrow 8CO_2+10H_2O$

Butane is the limiting reagent as it limits the formation of product and oxygen is in excess and is the excess reagent.

2 moles of butane gives 8 moles of carbon dioxide

Thus 0.0172 moles of butane gives=$\frac{8}{2}\times 0.0172=0.0688moles$  of carbon dioxide

Mass of $CO_2$ produced=$moles\times {\text {Molar mass}}=0.0688\times 44=3g$

Thus 3 g of  $CO_2$ is produced.