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 124 kJ is given off per mole of C2H4 reacting, how much heat is released when 14.6 kg of C2H6 forms?

Answer 1

C2H4 + H2 ==> C2H6
124 kJ is released when 1 mole C2H4 reacts and 1 mole C2H6 is formed. The molar mass C2H6 is 30.07 grams. We can restate the problem that 124 kJ heat is released in forming 30.07 g C2H6.
124 kJ released x 14.6 kg/0.0307 kg = ??

Answer 2

58970 ? But, it has to be 3 significant figures, right ? So, would it be 5.90e4

Answer 3

48970.68 kJ which you need to round to 3 s.f.

Answer 4

How much energy is required to heat 1.3 g of
gold from 25
◦
C to 46
◦
C? The specific heat of
gold is 0.131 J/g·
◦
C.