CC9 - Calculating Involving Masses (p26-30) 2. Using the periodic table – find the mass of the elements below using a periodic table 3. Relative formula mass - calculate the formula mass of the following compounds H20 CO2 CH4 NH3 H2SO4 (NH3)2NO3 1. Define - Formula mass Atomic Mass Empirical formula Yield 1: O 2: C 3:Mg 4:Ca 5:N 4. Empirical formula (the simplest ratio of atoms in a compound) e.g. The empirical formula of C2H4 (ethene) is CH2. What is the empirical formula of the following? C2H6 C4H8 H2O C6H12O6 In a reaction 20g of calcium reacts with 6g of carbon and 24g of oxygen. 5. Calculating % yield - identify two figures, the predicted yield and the actual yield the use the equation: % Yield = Actual Yield x 100 Predicted yield Calculate predicted yield in the following experiment. 40g of CO2 produced when CaCO3 is heated when the expected yield was 44g 80g of CaCO3 produced when CaCO3 heated when the expected yield was 100g 7. Calculating concentration - divide the mass dissolved by the volume (in litres). Concentration (g/dm3)= mass (g) volume (dm3) 1 25g of copper sulphate is dissolved in 500cm3 of water. 2 What is the mass of sodium chloride in 300cm3 of solution with concentration of 12g/dm3 8. (Higher) Moles is the name given to a certain number of particles. 1 mole = 6.02x1023 particles How many particles in a mole of oxygen? How many particles in 4 moles of nitrogen? 9. (Higher) Moles - calculating the number of moles in a mass of compound. Use the equation Number of moles = Mass of compound Formula mass of compound How many moles in 18g of H2O. How many moles in 200g of CaCO3. How many moles in 48g of CH4. What is the mass of 4 moles of CO2 6. Converting dm3 --> cm3 1000 cm3 = 1 dm3 = 1 litre 20 cm3 = _____dm3 _____cm3 = 0.76dm3

CC9 Calculating With Mass (p26-30) Moles is the name given to a certain number of particles. It is 6.02x1023. How many particles in a mole of oxygen? 6.02 x 1023 How many particles in 4 moles of nitrogen? 2.4 x 1024 Calculating % Yield. You need to identify two figures, the predicted yield and the actual yield the use the equation: % Yield = Actual Yield x 100 Predicted yield Calculate predicted yield in the following experiment. 40g of CO2 produced when CaCO3 is heated when the expected yield was 44g 91% 80g of CaCO3 produced when CaCO3 heated when the expected yield was 100g 80% Define: Formula mass: mass of all atoms in a molecule or compound Atomic Mass: mass of protons and neutrons Empirical formula: simplest ration of atoms in a compound Yield: mass produced in an experiment You must use the mass figures from the periodic table symbols Calculating the number of moles in a mass of compound. Use the equation Number of moles = Mass of compound Formula mass of compound How many moles in 18g of H2O. 1 How many moles in 200g of CaCO3. 2 How many moles in 48g of CH4. 3 What is the mass of 4 moles of CO2 176 What is the mass of the following elements? 1,O 16 2,C 12 3, Mg 24 4, Ca 40 5, N 14 Finding empirical formula. Calculating concentration. Simply divide the mass dissolved by the volume (in litres). Concentration (g/dm3)= mass (g) volume (dm3) 1 25g of copper sulphate is dissolved in 500cm3 of water. 50g/dm3 2 What is the mass of sodium chloride in 300cm3 of solution with concentration of 12g/dm3 3.6g Calculate the formula mass of the following compounds? H20 18 CO2 44 CH4 16 NH3 17 H2SO4 98 (NH3)2NO3 96 Find the empirical formula in the following: In a reaction 20g of calcium reacts with 6g of carbon and 24g of oxygen. CaCO3 1dm3 = 100cm3 =1000ml = 1litre Empirical formula is the simplest ratio of atoms in a compound. e.g. The empirical formula of C2H4 (ethene) is CH2. What is the empirical formula of the following? C2H6 CH3 C4H8 C2H4 H2O H2O C6H12O6 CH2O