Unit 7: Stoichiometry

3 CaCO₃ + 2 FePO₄ --> Ca₃(PO₄)₂ + Fe₂(CO₃)₃ Assuming we start with 100 g of CaCo₃ and 45 g of FePO₄, identify the limiting reactant.

Iron(iii) phosphate

CH₄ + 2 H₂O --> CO₂ + 4 H₂ What is the limiting reactant when 20g CH4 react with 15g H2O?

H₂O

What are the steps to solving stoichiometry problems?

1) Balance the chemical equation 2) Convert from given quantity to moles of reactant 3) Use mole ratio to convert from moles of reactant to moles of product 4) Convert from moles of product to desired quantity

What are the steps to determining the limiting reactant?

1) Balance the chemical equation 2) Convert the given information to # of moles of reactant (do this for each reactant) 3) Use the mole ratio to convert to moles of product for each reactant 4) The limiting reactant is the one that produces the fewest # of moles of product

3NH4NO3 + Na3PO4 --> (NH4)3PO4 + 3 NaNO3 Assuming we start with 30 g of NH4NO3 and 50 g of Na3PO4, identify the limiting reactant.

Ammonium nitrate

Use the equation 2 Al + 3 Cl2 ---> 2 AlCl3. If 2 moles of aluminum and 2 moles of chlorine are reacted, identify the limiting reactant.

Cl2

What is the limiting reactant if 10 moles of NH3 react with 30.0 moles of NO? 4NH3+6NO --> 5N2 + 6H2O

NH3

P4 + 3O2 --> P4O6 What is the limiting reactant is 12 moles of P4 react with 15 moles of O2?

O2

When 12 moles of O2 reacts with 1.1 mole of C10H8 what is the limiting reactant? C10H8 + 12 O2 --> 10 CO2 + 4 H2O

Oxygen

P₄ + 3O₂ —> P₄O₆ What is the limiting reactant if 12 moles of P₄ react with 15 moles of O₂?

O₂

What happens once the limiting reactant is used up?

The chemical reaction stops taking place and all other reactants are left in excess.

What is stoichiometry?

The quantitative relationships between reactants and products

What is mole ratio?

The ratio between amounts of reactants and products, given by the coefficients of the balanced equation

What is the limiting reactant?

The reactant that is used up first

What can stoichiometry be used for?

To compare amounts of whole subjects to amounts of its components