Question

50 grams of benzene (C₆H₆) is placed in a containr with 160 g of oxygen gas. What kind of reaction is this? why ?
C₆H₆ + O₂ ------> H₂O + CO₂
1. Balance the equation.

2. Which starting material is limiting reagent?

3. How much excess reactant is left over for reaction?

4.After combustion 30 grams of water is collected what is the percent yield?

Answer 1

1) balanced equation:

2 C₆H₆ + 15 O₂ ------> 6 H₂O + 12 CO₂

2)

2 C₆H₆ +   15 O₂ -----------------------------> 6 H₂O + 12 CO₂

156 g         480 g

50 g            160 g

156 g C6H6 ------------------------------> 480 g O2

50 g C6H6 -------------------------------> 480 x 50 / 156 = 153.8 g O2 needed . but we have excess O2. so it O2 is excess reagent .

limiting reagent is C6H6

3)

excess reagent left = 160 - 153.8

                            = 6.15 g

4)

water produced thereotically = 108 x 50 / 156

                                          = 34.6 g

percent yield = actal x 100 / theoretical

                    = 30 x 100 / 34.6

                   = 86.7 %

percent yield = 86.7 %