Question

1. Calculate the enthalpy change for the reaction based ion the given information:  2CH4(g) + 2O2(g) --> CH2CO(g) + 3H2O(g)

CH2CO(g) + 2O2(g) --> 2CO2(g) + H2O(g) Delta H = -941.1 kJ
CH4(g) + 2O2(g) --> CO2(g) + 2H2O(g) Delta H = -882.3 kJ

2. Suppose a large size chocolate fudge ice cream gives 162 Calories. If an ice cream contains 6.00 g of carbohydrate and 12.0 g of protein then find out grams of fat? [1g Fat = 9kcal, 1g Protein = 4kcal, and 1g Carbohydrate = 4kcal]

Answer 1

1.

Given:

CH₂CO(g) + 2O₂(g) --> 2CO₂(g) + H₂O(g)    Delta H₁ = -941.1 kJ

Delta H for the reverse reaction will be positive

2CO₂(g) + H₂O(g) --> CH₂CO(g) + 2O₂(g) Delta H₂ = 941.1 kJ                .......(1)

CH₄(g) + 2O₂(g) --> CO₂(g) + 2H₂O(g)              Delta H₃ = -882.3 kJ           

2CH₄(g) + 4O₂(g) --> 2CO₂(g) + 4H₂O(g)              Delta H₄ = - 1764.6 kJ             .......(2)

we have to caluclate enthalpy change for the following reaction

2CH4(g) + 2O2(g) --> CH2CO(g) + 3H2O(g)

From the equation 1 and 2

Delta H = delta H₂ + delta H₃ = 941.1 + ( - 1764.6) = -823.5 kJ