Chemistry 11 : Stoichimmetry

The study of the relationships between the quantities of reactants and products involved in chemical reactions

Using a balanced chemical equation Predict the amounts of any regeants consumed or product created knowing the amount of any one reactant consumed or product ceated

The balanced chemical equation tells you how many molecules are consumed or producted within a chemical reaction ⇒  This can be scaled up from molecules to the number of moles

N2(g) + 3H2 (g) -> 2NH3 (g)

1 molecule/1mol 3 molecules 3mol 2 molecules 2 mol

If 1 mol of N2 reacts, then 3 mol of H2 react 2 Mol of nH3 is produced

If 2 mol of N2 reacts 6 ol of H2 reacts 4 mol of NH3 is produced

If 30 mol of hydrogen of H2 10 mol of nitrogen2 reacts and 20 mol of NH3 is produced

If 0.50 mole of Nh3 is produced 0.25 mol of N2 reacts 0.75mol of H2 reacts

The balanced chemical equation gives you the ratio between the number of molecules or moles of the reactants and products

Using unit analysis this is called The molecular raitof or molecules

The mole ratio for number of moles used most often

Example ⇒  For the reaction C2H6(g) + 7O2(g) -> 4CO2(g) + 6H2O(g)

If 0.350 mol of C2H6 reacts

How many moles of O2 will react?

How many moles of CO2 and H2O are produced?

N [o2] = 0.350 mol C2H6 * 7 mol O2/ 2 mol C2H6 Mole ratio -> uses the coefficients from the balanced chemical reaction 1.225 mol

n[co2] = 0.350 mol C2H6 * 4mol Co2 / 2mol C2H6 = 0.7mol n[H2O] 0.350mol C2H6 * 6mol H2O / 2mol C2H6 = 1.050mol

2H2(g) + O2(g) -> 2H2O(L)

2 Hydrogen molecules for every oxygen molecule for every 2 water molecules 2:1:2 100 hydrogen means 50 oxygens will be needed 4956 water molecules will be produced

2 mols of hydrogen are needed 2:3:2 4:6:4 5:7.2:5 7.2 mols are needed to produce 5 mols of Albr