Question

Organic hydrogenation reactions, in which H₂ and an "unsaturated" organic compound combine, are used in the food, fuel, and polymer industries. In the simplest case, ethene (C₂H₄) and H₂ form ethane (C₂H₆). If 135 kJ is given off per mole of C₂H₄ reacting, how much heat is released when 14.7 kg of C₂H₆ forms?

Answer 1

The answer is: 6.6150 × 10⁴ kJ

Step-by-step explanation:

Given reaction: C₂H₄ (ethene) + H₂ → C₂H₆ (ethane)

Given: Heat of hydrogenation of ethene = 135 kJ/mol

given mass of ethane = 14.7 kg = 14700 g (∵ 1 kg = 1000g)

Molar mass of ethane = 30 g/mol

The number of moles of ethane = given mass ÷ molar mass = 14700 g ÷ 30 g/mol = 490 moles

As 1 mole ethene gives 1 mole ethane on hydrogenation.

Therefore, number of moles of ethane = number of moles of ethene = 490 moles

Therefore, the heat of hydrogenation for the formation of 490 moles (14.7 kg) ethane = 490 mol × 135 kJ/mol = 66150 kJ = 6.6150 × 10⁴ kJ