What mass of ethanol is obtained when 5.68 g of carbon dioxide is produced during fermentation, at 25°C and 100 kPa? (A) 2.95 g (B) 5.95 g (C) 33.6 g (D) 147.2 g - HSC - SSCE Chemistry - Question 15 - 2010 - Paper 1

The fermentation process can be represented by the balanced chemical equation:

$C_6H_{12}O_6 \rightarrow 2 C_2H_5OH + 2 CO_2$

From this equation, we see that 2 moles of ethanol are produced for every 2 moles of CO₂ produced. Therefore, the number of moles of ethanol (C₂H₅OH) produced is equal to the moles of CO₂:

$n_{C_2H_5OH} = n_{CO_2} \approx 0.129 \text{ mol}$

To find the mass of ethanol produced, we use the molar mass of ethanol, which is approximately 46.07 g/mol:

$m_{C_2H_5OH} = n_{C_2H_5OH} \times 46.07 \text{ g/mol} \approx 0.129 \text{ mol} \times 46.07 \text{ g/mol} \approx 5.95 \text{ g}$