1. Chemical Quantities

2.  Calculate the mass of compounds.  Calculate the molar volumes of gases.  Solve problems requiring conversions between mass, and number of particles, and moles.

3. The mole allows the conversion between mass and number of particles. In one mole there is 6.02 x 10 23 particles.

4. 22.4 L Molar Volume

5. Avogardo (1776-1856) Avogadro’s Hypothesis - any sample of any gas at the same temperature and pressure will contain the same number of particles.

6. Chemists use a standard temperature and pressure, STP, to measure gas volumes. 0°C and 101.3 kPa At STP: The volume of 1 mole of ANY GAS is 22.4 L. 22.4 L/mol is known as molar volume. The MASS of 22.4 L of any gas is equal to the molar mass for that gas.

7. How many moles are in 50.0 L of Fluorine gas at STP? F 2 = 36.0 g/mol 50.0 L 22.4 L 1 mol = 2.23 mol

8. What is the STP volume of 10.0 g of Methane gas? CH 4 = 16.0 g/mol 10.0 g 16.0 g 1 mol = 14.0 L 1 mol 22.4 L

9. Density: A physical property that describes the mass per unit volume of a substance. grams (g) per litre grams per mL (or cm 3 )

10. Calculate the volume, in litres, of one mole of ammonia (NH 3 ) at room temperature if the density is 0.696 g/L. NH 3 = 17.0 g/mol 1 mol 17. 0 g = 24.4 L 0.696 g 1 L

11. Calculate the volume, in litres, of two moles of carbon dioxide, at room temperature, when the density is 1.80 g/L. CO 2 = 44.0 g/mol 2 mol 1 mol 44. 0 g = 48.9 L 1.80 g 1 L

13. · STP 0°C and 101.3 kPa (1 atm). · At STP, the molar volume of any gas is 22.4 L (L/mol) · Molar mass = total grams in 1 mole g(/mol). · 1 mole = 6.02 x 1023 particles (Avogadro) · density of a substance = mass per volumeg (/L) · All roads lead to moles (convert to moles first).