chemistry hmw pls help?

[Greg V]

Consider the following equation:
4NH3(g) + 5O2---------> 4NO(g) + 6 H2O (g)


2.How many grams of water vapor can be produced from 25L NH3 if both gases are at STP?

3.How many litres of NO can be produced when 25L O2 are reacted with 25L NH3? All gases are at the same tempertature and pressure.

[j.investi]

4 NH3 + 5 O2 --> 4 NO + 6 H2O

a) mole of NH3 = 25 / 22.4 = 1.12 mol
mole of H2O = 6/4 * mole of NH3 = 1.68 mol [ratio of coefficients = ratio of moles]
mass of H2O = 1.68 * 18 = 30.24g

b) assume the gases are at STP.

mole of O2 = 25 / 22.4 = 1.12 mol
mole of NH3 = 25 / 22.4 = 1.12 mol

limiting agent: O2. (to check, divide the mole of each reactant with its coefficient.
e.g. NH3: 1.12 / 4 = 0.28
O2: 1.12 / 5 = 0.224
0.224 < 0.28, thus O2 is the limiting agent)

mole of NO produced = 4/5 * mole of O2 = 0.896 mol
volume = 0.896 * 22.4 = 20.07 L