Hydrogen and oxygen combustion: heat, limiting reactant, water produced

[jjackj232000]

2H2+O2=2H2O+242kJ (HEAT)
-How many grams of H2 gas are required to produce 2.21x103 kJ of heat?
-How many grams of H2 gas are required to react with 785 gm of O2 gas?
-If 300 gms of O2 gas and 75 gms of H2 gas are mixed and burned what is the limiting reactant?
-How many grams of H2O are produced in question above?

please help

 

[cristo]

Welcome to the forums. Please note that you are required to show working before we can help you. So, do you have any thoughts?

 

[jjackj232000]

help

Welcome to the forums. Please note that you are required to show working before we can help you. So, do you have any thoughts?

i have no idea

 

[TMM]

Remember that everything in a chemical equation is a ratio, including energy.

If 2 moles of H2 gives you 242kJ, what mass of H2 gives you 242kJ? Now what mass of H2 do you need for your desired amount of energy?

 

[jjackj232000]

do i multiply H2 mass by 2210? is 2 the mass of H2?

 

[ace123]

Yes the mass of H2 is 2, don't you have a periodic table of elements? What TMM was trying to say is that if you have 2 moles of H2 that gives 242 KJ. How many moles would give you 2.21x103 kJ. It's just a simple ratio

 

[jjackj232000]

thank u, TMM and ace123