Consider the gas-phase reaction of ethylene (C2H4) with hydrogen (H2) to form ethane (C2H6), which occurs in the presence of a palladium catalyst.

Part: 0 / 7

Part 1 of 7

Write a balanced equation for this equilibrium. Do not include the palladium catalyst. Include all physical states of matter.

C2H4(g)+ H2(g)= C2H6 (g)

x

Part: 1 / 7

How much energy is released when 21.0 g of ethylene reacts? Be sure your answer has the correct number of significant figures.

kcal released

1 answer

The enthalpy change for the reaction of ethylene with hydrogen to form ethane is -136.2 kcal/mol.

First, we need to calculate the moles of ethylene in 21.0 g.

Molar mass of C2H4 = 2(12.01) + 4(1.008) = 28.05 g/mol
Moles = 21.0 g / 28.05 g/mol = 0.749 mol

Now, we can calculate the energy released when 0.749 mol of ethylene reacts.

Energy released = 0.749 mol x (-136.2 kcal/mol) = -101.9 kcal

Therefore, 101.9 kcal of energy is released when 21.0 g of ethylene reacts.