Question

Yield of chemical reactions

Gaseous ethane (CH,CH,) reacts with gaseous oxygen gas (0₂) to produce gaseous carbon dioxide (CO₂) and gaseous water (H₂O). What is the theoretical
yield of water formed from the reaction of 3.01 g of ethane and 19.3 g of oxygen gas?
Round your answer to 3 significant figures.

Answer 1

The balanced chemical equation for the reaction is:

2 C2H6 + 7 O2 → 4 CO2 + 6 H2O

From the equation, 2 moles of ethane react with 7 moles of oxygen gas to produce 6 moles of water.

First, we need to determine which reactant is limiting. To do this, we can use the given masses and convert them to moles using the molar masses of the compounds:

n(C2H6) = 3.01 g / 30.07 g/mol = 0.100 mol

n(O2) = 19.3 g / 32.00 g/mol = 0.603 mol

The mole ratio of C2H6 : O2 is 2 : 7, so to react completely with 0.100 mol of C2H6, we need:

n(O2) = (7/2) x 0.100 mol = 0.350 mol

Since we have more than 0.350 mol of O2, O2 is not the limiting reactant. Therefore, the limiting reactant is C2H6.

The theoretical yield of H2O can be calculated from the number of moles of C2H6:

n(H2O) = (6/2) x 0.100 mol = 0.300 mol

Finally, we can convert the number of moles of H2O to grams:

m(H2O) = n(H2O) x M(H2O)

m(H2O) = 0.300 mol x 18.02 g/mol

m(H2O) = 5.41 g

Therefore, the theoretical yield of H2O formed is 5.41 g. Rounded to three significant figures, the answer is 5.41 g.

Step-by-step explanation: