Stoichiometry Ap chem

Question

you are given this balanced equation

4 NH3 + 6 NO —> 5 N2 + 6 H2O

12.5 moles of NO require how many grams of NH3 to react completely?

Answer 1

The balanced reaction equation says for every 6 moles of NO, you must have 4 moles oh NH₃. So, given that you start with 12.5 moles of NO:

To calculate the mass of NH₃, you must use the molar mass. From the Periodic Table:

N = 14.007 g/mol

H = 1.008 g/mol x 3 = 3.024 g/mol

NH₃ = 14.007 + 3.024 = 17.031 g/mol

Since there are 8.333 moles required then:

Rounding to 3 sig figs yields 142 g NH₃