Stoichiometry

• balanced chemical equations tell us the ratio in which chemicals are consumed/produced

• these are in units of moles

• we can use these ratios to calculate amounts of chemicals

• write the ratio as a fraction, usually with unknown chemical on top

ex. 3H2 + N2 → 2NH3

I want to make 14 moles of ammonia, calculate how much H2 I need

n(H2) = 3 = n(H2)

n(NH3) 2 14