Question

Gaseous ethane (CH3CH3) reacts with gaseous oxygen gas (0₂) to produce gaseous carbon dioxide (CO₂) and gaseous water (H₂O). If 69.7 g of carbon

dioxide is produced from the reaction of 26.76 g of ethane and 169.4 g of oxygen gas, calculate the percent yield of carbon dioxide.
Round your answer to 3 significant figures.

Answer 1

The balanced chemical equation for the reaction is:

C2H6 + 3O2 → 2CO2 + 3H2O

To calculate the theoretical yield of CO2, we need to use the given amount of ethane and oxygen gas to determine which reactant is limiting, and then use stoichiometry to calculate the amount of CO2 that should be produced.

First, we need to calculate the number of moles of ethane and oxygen gas used in the reaction:

moles of ethane = 26.76 g / 30.07 g/mol = 0.8908 mol

moles of oxygen gas = 169.4 g / 32.00 g/mol = 5.304 mol

Next, we need to determine which reactant is limiting by comparing the number of moles of each reactant to their stoichiometric coefficients in the balanced equation. The stoichiometric ratio of ethane to oxygen gas is 1:3, so every one mole of ethane requires three moles of oxygen gas. Therefore, the limiting reactant is ethane, because there are only 0.8908 moles of it, whereas there are 5.304 moles of oxygen gas.

Using the stoichiometry of the balanced equation, we can calculate the theoretical yield of CO2:

moles of CO2 = moles of ethane × (2 moles of CO2 / 1 mole of C2H6) = 0.8908 mol × 2 = 1.7816 mol

mass of CO2 = moles of CO2 × molar mass of CO2 = 1.7816 mol × 44.01 g/mol = 78.5 g

Now, we can calculate the percent yield of CO2:

percent yield = (actual yield / theoretical yield) × 100%

actual yield = 69.7 g

percent yield = (69.7 g / 78.5 g) × 100% = 88.7%

Therefore, the percent yield of CO2 is 88.7%.