Presentation on theme: "Aim: How to convert from moles to volume and vice versa"— Presentation transcript:
1 Aim: How to convert from moles to volume and vice versa
2 Avogardo’s Hypothesis Avogadro's hypothesis says that the same volume of gas contains the same number of particles. It does not matter what gas you have, they all contain the same number of particles provided that they are at the same temperature and pressure.
3 STPVolume of gas and temperature are usually measured at STP.Standard temperature and pressure (STP) means temperature of 0oC and a pressure of kPa, or 1 atmosphere (atm).At STP, 1 mole or 6.02 x representative particles of any gas occupies a volume of 22.4 L.
6 Calculating from moles of gas to volume of gas Volume of gas = moles of gas x 𝐿 1 𝑚𝑜𝑙Conversion Factor
7 Calculating the volume of a gas at STP Determine the volume, in liters, of 0.60 mol SO2 gas at STP.Identify known and unknown.Known Unknown1 mol = 22.4 L volume of 0.60 mol SO20.60 mol SO2
8 2. Set up equation Volume = 0. 60 mol SO2 x 22 2. Set up equation Volume = 0.60 mol SO2 x 22.4 𝐿 1 𝑚𝑜𝑙 SO2 Volume = 13 L SO2
9 What is the volume of these gases at STP? 3.20 x 10-3 mol CO23.20 x 10-3 mol CO2 x 22.4 L / 1 mol = L CO2b mol N23.70 mol N2 x 22.4 L / 1 mol = 82.9 L N2
10 Converting from volume of gas to moles of gas Conversion FactorMoles of gas = volume of gas x 1 𝑚𝑜𝑙 22.4 𝐿
11 Calculating number of moles of a gas at STP How many moles of helium at STP will fit into a 39.6 L container?Identify known and unknown.Known Unknown1 mol = 22.4 L # of moles39.6 L
12 Moles = 1.77 mol He 2. Set up equation Moles = 39.6 L He x 1 𝑚𝑜𝑙𝑒 𝐻𝑒 22.4 𝐿 𝐻𝑒Moles = 1.77 mol He
13 How many moles of argon atoms are present in 11 How many moles of argon atoms are present in 11.2 L of argon gas at STP?11.2 x 1mol / 22.4 L = moles
14 Calculating Molar Mass From Density Reminder: Density= mass / volumeDensity = molar mass / molar volumeMolar mass = density x molar volume𝑔𝑟𝑎𝑚𝑠 𝑚𝑜𝑙𝑒 = 𝑔𝑟𝑎𝑚𝑠 𝑙𝑖𝑡𝑒𝑟𝑠 x 𝐿 1 𝑚𝑜𝑙𝑒Molar volumeMolar Massdensity
15 Calculating molar mass of gas at STP The desnity of a gaseous compound containing carbon ad oxygen is found to be g/L at STP. What is the molar mass of this compound.List known and unknown.Known UnkownDensity = g/L molar mass ?1 mol = 22.4 L
16 Molar mass = 1.964 𝑔 1 𝐿 x 22.4 𝐿 1 𝑚𝑜𝑙 Molar mass = 44.0 g/mol 2. Set up equation.Molar mass = 𝑔 1 𝐿 x 𝐿 1 𝑚𝑜𝑙Molar mass = 44.0 g/mol
17 What is the density of krypton gas at STP Find molar mass of kryptonmolar mass = 83.8 g/mol2. Set up EquationDensity (g/L) = molar mass/ molar volumeDensity= 𝑔/𝑚𝑜𝑙 22.4 𝐿/𝑚𝑜𝑙 or Density= (83.8 g/1 mol) x (1 mol / 22.4 L)Density of Kr = 3.74 g/L