[needhelp213]

Please understand that I am not asking for someone to do these problems for me, but I am merely asking for someone to give me a walkthrough of how to do them so in the future, I will be able tto understand them. I real have no clue how to do this.

U(s) + 3F2 (g) --> UF6 Delta H=-2113KJ

How much heat is released when 1.00 Kg of uranium reacts with flourine?

N2H4 (g) + O2 (g) --> N2 (g) + 2H20 (I) Delta H=-628 KJ

How many grams of Hydrazine (N2H4) would be required to produce 963 KJ of heat?

If the reaction was at standard temperature and pressure, how many liters of N2 gas would evolve if the amount of N2H4 found in part (a) was burned?

Again, I am not asking for answers. These are from a HW worksheet where I understood the first 17 question, but have no clue how to do the last 3. I am mainly asking for answer because I have my exam tommorow and I want to know how to do problems like these.

[Yggdrasil]

U(s) + 3F2 (g) --> UF6 Delta H=-2113KJ

How much heat is released when 1.00 Kg of uranium reacts with flourine?

The Delta H tells you the amount of heat produced per mole of reaction.  So, in this case, when one mole of uranium reacts with three moles of fluorine gas to produce one mole of uranium fluoride, 2113kJ are released (a negative delta H tells you that heat is released, a positive delta H tells you that heat is taken up by the system).

So, to find how much heat, find how many moles of uranium are reacting.