a) if the molar enthalpy for uranium 235 is 1.9 x 10^10 KJ/mol, how much energy can be obtained from the fission of 1.00 k (4.26 mol) of pure uranium-235?

b) In the sun, hydrogen atoms undergo nuclear fusion to produce He and 1.7 x 10^9 kj/mol He. How much energy can be obtained by producing 1.00 kg of helium?

The answers are a) 8.1 x 10^10 kj
b) 4.3 x 10^11kj

I just dont understand the steps!! please help

Question

a) if the molar enthalpy for uranium 235 is 1.9 x 10^10 KJ/mol, how much energy can be obtained from the fission of 1.00 k (4.26 mol) of pure uranium-235?

b) In the sun, hydrogen atoms undergo nuclear fusion to produce He and 1.7 x 10^9 kj/mol He. How much energy can be obtained by producing 1.00 kg of helium? 

The answers are a) 8.1 x 10^10 kj
b) 4.3 x 10^11kj

I just dont understand the steps!! please help

anonymous · Answer

For the first one, you just multiply the molar enthalpy for Uranium 235 with the fission of 1k pure uranium 235. 1.9 x 10^10 KJ/mol * 4.26 mol =~8.1 x 10^10 kj
Not sure about the second one.