Question

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

Answer 1

Answer:

Percentage yield = 68.3%

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%