Stoichiometry: mol-to-mol ratios calculations of quantities in chemical rxns –how much reactant is needed or –how much product is formed Balanced chemical equations show the amount of: atoms, molecules, moles, and mass Most important are the ratios of reactants and products in moles, or… mol-to-mol ratios

Atoms

Molecules

Moles

Mass

Mass and atoms are conserved in every chemical reaction Mass & Atoms Mass and atoms are conserved in every chemical reaction

Atoms Mass Molecules Moles 2 H2S(g) + 3 O2(g)  2 SO2(g) + 2 H2O(g) Interpret this equation in terms of: Atoms Mass Molecules Moles 12 12 164.16 g 164.16 g 5 4 5 4

3 W + F + H + 2 P + S → TRIKE Quick Quiz! A manufacturer of tricycles has 15 wheels(W), 6 frames(F), 5 handlebars(H), 12 seats(S), and 8 pedals(P). How many tricycles can be manufactured using these parts? 5 tricycles 3 tricycles 6 tricycles 4 tricycles 3 W + F + H + 2 P + S → TRIKE

Quick Quiz. 2. What is the most important information from a chemical equation? states of matter moles of products mole ratios of reactants & products masses of reactants and products