1. Review When converting FROM moles you MULTIPLY.
Multiplier is on TOP
When converting TO moles you DIVIDE.
Divider is on BOTTOM

2. Interpreting Chemical Equations
Chapter 9

3. Information from Equations
Particles - Ratio
Moles - Ratio
Mass – Conservation of mass
Volume – 1mol at STP = 22.4L

4. “Mass and atoms are conserved in every chemical reaction, but moles will not necessarily be conserved.”

5. 2H2S + 3O2  2SO2 + 2H2O
The coefficients in the balanced equation give the relative number of molecules and moles of reactants and products.
A balanced chemical equation obeys the law of conservation of masses.
The sum of the masses of reactants equals the sum of the masses of products.

6. 2H2S + 3O2  2SO2 + 2H2O
2 molecules of H2S react with 3 molecules of O2 to form 2 molecules of SO2 and 2 molecules of H2O.
2 moles of H2S react with 3 moles of O2 to form 2 moles of SO2 and 2 moles of H2O.
Mole Ratio: 2:3:2:2
2mol(34.1g/mol) + 3mol(32.0g/mol) = 164.2g
2mol(64.1g/mol) + 2mol(18.0g/mol) = 164.2g

7. Mole-Mass
Multiplying the number of moles of a substance by its molar mass give the mass of the substance.
Dividing the mass of a substance by its molar mass give the number of moles of that substance.

8. Mole-Volume
One mole of any gas at STP (1atm pressure and 0 degrees C) occupies a volume of 22.4L.
The density f any gas at STP is its molar mass divided by 22.4L

9. Chapter 9 Page 241
Section Review 9.1
# 6-8