Question

Liquid hexane CH3CH24CH3 reacts with gaseous oxygen gas O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O .

If 0.273g of water is produced from the reaction of 0.86g of hexane and 0.94g of oxygen gas, calculate the percent yield of water.

Be sure your answer has the correct number of significant digits in it.

Answer 1

Percentage yield = 68.3%

Step-by-step explanation:

Given data:

Mass of water = 0.273 g

Mass of hexane = 0.86 g

Mass of oxygen = 0.94 g

Percent yield = ?

Solution:

2C₆H₁₄ + 19O₂ → 12CO₂ + 14H₂O

Moles of hexane:

Number of moles = mass/ molar mass

Number of moles = 0.86 g / 86.18 g/mol

Number of moles = 0.01 mol

Moles of oxygen:

Number of moles = mass/ molar mass

Number of moles = 0.94 g / 32 g/mol

Number of moles = 0.03 mol

Now we will compare the moles of oxygen and hexane with water:

O₂ : H₂O

19 : 14

0.03 : 14/19×0.03 = 0.022 mol

C₆H₁₄ : H₂O

2 : 14

0.01 : 14/2×0.01 = 0.07 mol

Number of moles of water produced by oxygen are less so it will limiting reactant.

Mass of water:

Mass = number of moles × molar mass

Mass = 0.022 mol × 18 g/mol

Mass = 0.4 g

Percentage yield:

Percentage yield = Actual yield / theoretical yield × 100

Percentage yield = 0.273 g / 0.4 g × 100

Percentage yield = 0.683 × 100

Percentage yield = 68.3%