Consider the reaction, C2H4 (g) + H2 (g)- C2H6 (g) where -137kJ of heat is released.

Question

How many kilojoules are released when 55.3g of C2H4 reacts?

Answer 1

137 kJ heat released for 28 g C2H4. You have 55.3g; therefore, heat released will be 137 kJ x (55.3/28) = ??
Another way to look at it.
This is 137 kJ heat released per mol C2H4.How many moles do you have?
That is 55.3/28 = 1.975 moles
Then 1.37 kJ/mol x 1.975 mol = ??

Answer 2

480kj

Answer 3

270. kJ are released.