Problem :

 4NH3(g) + 6NO(g)→5N2(g) + 6H2O(g)

How many moles of each reactant were there if 13.7 moles of N2(g) is produced? ×4 moles NH3(g) = 10.96 moles NH3(g) ×6 moles NO(g) = 16.44 moles NO(g)

So we have 10.96 moles NH3(g) and 16.44 moles NO(g).

Problem : What is the mass of 2 moles of H2S?

GFM of H = 1
GFM of S = 32>br> GFM of H2S = 2×1 + 32 = 34 grams / mole ×34 grams = 68 grams

Problem : 2Al +3Cl2→2AlCl3

When 80 grams of aluminum is reacted with excess chlorine gas, how many formula units of AlCl3 are produced? ×1 mole Al = 2.96 moles Al

There is a 1:1 ratio between Al and AlCl3, therefore there are 2.96 moles AlCl3. = 1.78×1025

Problem : Sb2S3(s) + 3Fe(s)→2Sb(s) +3FeS(s)

If 3.87×1023 particles of Sb2S3(s) are reacted with excess Fe(s), what mass of FeS(s) is produced? ×1 mole Sb2S3(s) = 0.643 moles Sb2S3(s) ×3 moles FeS(s) = 1.93 moles FeS(s) ×88 grams = 170 grams

Problem : CO(g) +2H2(g)→CH3OH(g)

At STP, what volume of H2(g) is needed to react completely with 8.02×1023 molecules of CO(g)? ×1 mole CO(g) = 1.33 moles CO(g) ×2 moles H2(g) = 2.66 moles H2(g) ×22.4 L = 59.7 L