Concentration Worksheet 1) How many grams of beryllium chloride are needed to make 125 mL of a 10% solution? 2) How many grams of beryllium chloride would you find in a 125 mL aqueous solution if the concentration was 50 ppm? CHANGES MADE TO QUESTION!! 3) The density of ethanol is 0.789 g/mL. How many grams of ethanol should be mixed with 225 mL of water to make a 4.5% (v/v) mixture? 4) Explain how to make at least one liter of a 5% m/v ammonium hydroxide solution. 5) What is the concentration (in g/L, ppm and %) of a solution in which 0.45 grams of sodium nitrate are dissolved in 265 mL of solution. 6) What is the concentration (in g/L, ppm and %) of sulfuric acid in a solution made by adding 3.4 grams of sulfuric acid to 3,500 mL of water? 7) What will the volume of a 0.50 g/L solution be if it contains 25 grams of calcium hydroxide? 8) How many grams of ammonia are present in 5.0 L of a 500 ppm solution? © 2004 Cavalcade Publishing, All Rights Reserved For chemistry help, visit www.chemfiesta.com Concentration Worksheet – Answers 1) How many grams of beryllium chloride are needed to make 125 mL of a 10% solution? 10%m/m = (x/125mL) x 100, x = 12.5g 2) How many grams of beryllium chloride would you find in a 125 mL aqueous solution if the concentration was 50 ppm? 50ppm = 50mg/L, 50mg/L = 0.05g/L, 0.05g/L = x/0.125L, x = 0.00625g 3) The density of ethanol is 0.789 g/mL. How many grams of ethanol should be mixed with 225 mL of water to make a 4.5% (v/v) mixture? 4.5%v/v = {x mL / (225mL + x mL)} x 100, x = 10.60 mL 10.60 mL X 0.789g/mL = 8.37g 4) Explain how to make at least one liter of a 5% m/v ammonium hydroxide solution. 5% m/v = (x g/1000mL) x 100, x = 50g of solute to be added to a volumetric flask and fill with solvent until a total volume of 1L is achieved. 5) What is the concentration (in g/L, ppm and %) of a solution in which 0.45 grams of sodium nitrate are dissolved in 265 mL of solution. g/L = 0.45g/0.265L= 1.70g/L, ppm = 450mg/0.265L = 1698 ppm, %m/v = (0.45g/265mL)x 100 = 0.17% 6) What is the concentration (in g/L, ppm and %) of sulfuric acid in a solution made by adding 3.4 grams of sulfuric acid to 3,500 mL of water? g/L = 0.97g/L, ppm = 0.00097ppm, %m/v = 0.097% 7) What will the volume of a 0.50 g/L solution be if it contains 25 grams of calcium hydroxide? 0.50g/L = 25g/ x L, x = 50L © 2004 Cavalcade Publishing, All Rights Reserved For chemistry help, visit www.chemfiesta.com 8) How many grams of ammonia are present in 5.0 L of a 500 ppm solution? 500 ppm = 500 mg/L = x/5.0 L, x = 2500 mg = 2.5g © 2004 Cavalcade Publishing, All Rights Reserved For chemistry help, visit www.chemfiesta.com