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Chemical Quantities. Calculate the mass of compounds. Calculate the molar volumes of gases. Solve problems requiring conversions between mass, and number of particles, and moles. The mole allows the conversion between mass and number of particles.
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Calculate the mass of compounds. • Calculate the molar volumes of gases. • Solve problems requiring conversions between mass, and number of particles, and moles.
The mole allows the conversion between mass and number of particles. In one mole there is 6.02 x 1023particles.
Molar Volume 22.4 L
Avogardo (1776-1856) Avogadro’s Hypothesis - any sample of anygasat the same temperature and pressure will contain the same number of particles.
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.
How many moles are in 50.0 L of Fluorine gas at STP? F2 = 36.0 g/mol 1 mol 22.4 L 50.0 L = 2.23 mol
What is the STP volume of 10.0 g of Methane gas? CH4 = 16.0 g/mol 1 mol 22.4 L 1 mol 16.0 g 10.0 g = 14.0 L
Density: A physical property that describes the mass per unit volume of a substance. grams (g) per litre grams per mL (or cm3)
Calculate the volume, in litres, of one mole of ammonia (NH3) at room temperature if the density is 0.696 g/L. 17. 0 g 1 L 0.696 g 1 mol NH3 = 17.0 g/mol 1 mol = 24.4 L
Calculate the volume, in litres, of two moles of carbon dioxide, at room temperature, when the density is 1.80 g/L. 44. 0 g 1 L 1.80 g 1 mol CO2 = 44.0 g/mol 2 mol = 48.9 L
· 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).