Hydrogen cyanide is produced industrially from the reaction of gaseous ammonia, oxygen and methane:

Question

2NH3(g) + 3O2(g) + 2CH4 -->2HCN + 6H2O(g)
a)If 5.00 x 10^3 kg each of NH3 , O2, and CH4 are reacted what mass of HCN will be produced, assuming 100% yield?
b)At the end of the reaction what are the masses of each of the reactants;NH3, O2, CH4

I got how to do part a) but i don't know how to do part B)

Answer 1

Part B is done the same way as part A; just do it three times.

Part B.
I assume from your post that you have the correct value for moles HCN.
Using the coerfficients in the balanced equation, convert moles HCN to
a. moles NH3.
b. moles O2.
c. moles CH4.

Now convert each of the a,b,c to grams. g = moles x molar mass.

Then subtract the amount you started with (5.00 kg of each) - the amount used in a,b, c above. the remainder is what is left after the reaction. One of those will be zero. Perhaps two can be zero. Probably all three are not zero.

Answer 2

so is this correct:
3330000 grams CH4
0 grams O2
1770833 grams NH3