For the reaction 2NH3(g) + O2(g) -> 2NO(g) + 3H2O(g). The reaction is run using 824 g NH3 and excess oxygen. How many moles of NO are formed? How many moles of H2O are formed?

Explanation:

Step One

Find the molar Mass of NH3

N =   14

3H =  3

Mass = 17

Step Two

Find the number of moles of NH3

mols = given mass / Molar Mass

given mass = 824 grams

molar mass = 17

mols = 824/17

mols =  48.47

Step Three

Find the moles of NO

Here you have to look at the balanced equation

Every 2 mols of HN3 produces 2 mols of NO

So the number of mols of NH3 = 48.47

The number of mols of  NO      = 48.47

Step Four

Find the mols of H2O

2 mols of NH3 produces 3 moles of H20

48.47 mols H20 produces x moles of H20

3/x = 2/48.47     Cross Multiply

2x = 3*48.47

2x = 145.41         Divide by 2

x = 145.41/2

x = 72.71            mols of water.