250 mL__|__1 L__ = 0.250 L | 1000 mL molarity = mole = 0.044 4 mol CsBr = 0.178 M CsBr liter 0.250 L Problems: 1. 145 g (NH4)2C4H4O6 in 500 mL of solution 2. 13.2 g MnSeO4 in 500 mL of solution 3. 45.1 g cobalt (II) sulfate in 250 mL of solution 4. 41.3 g iron (II) nitrate in 100 mL solution 5. 49.9 g Pb(ClO4)2 in 200 mL of solution 6. 35.0 g MnSiF6 in 50.0 mL of solution Percentage Composition Calculations To calculate the correct percentage composition of each element in some compound you must correctly follow several steps. It is not very difficult, once you get the hang of it. Please take notes on the steps to follow. Several problems follow this one for you to work. Lets look at a sample problem: magnesium chloride MgCl2 step 1: calculate formula mass Mg: 1 x 24.3 = 24.3 Cl: 2 x 35.4 = 70.8 ---- formula mass = 95.1 step 2: divide each component mass by the formula mass and multiply by 100
250 mL__|__1 L__ = 0.250 L | 1000 mL molarity = mole = 0.044 4 mol CsBr = 0.178 M CsBr liter 0.250 L Problems: 1. 145 g (NH4)2C4H4O6 in 500 mL of solution 2. 13.2 g MnSeO4 in 500 mL of solution 3. 45.1 g cobalt (II) sulfate in 250 mL of solution 4. 41.3 g iron (II) nitrate in 100 mL solution 5. 49.9 g Pb(ClO4)2 in 200 mL of solution 6. 35.0 g MnSiF6 in 50.0 mL of solution Percentage Composition Calculations To calculate the correct percentage composition of each element in some compound you must correctly follow several steps. It is not very difficult, once you get the hang of it. Please take notes on the steps to follow. Several problems follow this one for you to work. Lets look at a sample problem: magnesium chloride MgCl2 step 1: calculate formula mass Mg: 1 x 24.3 = 24.3 Cl: 2 x 35.4 = 70.8 ---- formula mass = 95.1 step 2: divide each component mass by the formula mass and multiply by 100
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