How many moles of CO2 are formed when 90 g of ethane is burned?

Let’s write the reaction equation:

2C2H6 + 7O2 = 4CO2 + 6H2O

Let’s find the amount of ethane substance:

v (C2H6) = m (C2H6) / M (C2H6) = 90/30 = 3 (mol).

According to the reaction equation, from 2 mol of C2H6, 4 mol of CO2 is formed, therefore:

v (CO2) = v (C2H6) * 4/2 = 3 * 4/2 = 6 (mol).

Thus, the resulting amount of carbon dioxide substance:

v (CO2) = 6 (mol).

Answer: 6 mol.