WORKSHOP 9 Solutions NAME Section 1 Calculate the by mass of solute in a solution containing a 8 32 g Lithium Arsenate in 45 0 g solution b 813 0 g Hydroiodic acid in 2811 g water 2 How many grams of sodium silicate are in 783 0 g of 27 0 sodium silicate solution 3 Describe how you would prepare 500 0 g of 2 55 potassium oxalate solution Show calculations and tell in words how much solute potassium oxalate and how much solvent deionized water you would mix Attach an extra page for your description if necessary 4 Calculate the molarity M of a solution containing a 1 52 moles of potassium hydroxide in 345 0 mL of solution b 47 8 g aluminum hydroxide in 5 67 liters of solution 5 How many grams of calcium arsenate are in 170 0 mL of 11 3 M calcium arsenate solution 6 How many moles of Perchloric acid are present in 25 00 mL of 0 324 M Perchloric acid solution 7 Describe in detail how you would prepare 0 675 liters of 1 50 M potassium sulfite solution a from 6 00 M potassium sulfite solution by dilution with water b from pure solid potassium sulfite 8 Aluminum hydroxide will react with sulfuric acid to yield aluminum sulfate and water a Write the balanced equation for this reaction b How many grams of aluminum hydroxide will react with 75 0 mL of 0 319 M sulfuric acid solution c If 0 875 g of aluminum hydroxide reacts exactly with 22 00 mL of a sulfuric acid solution what is the molarity of the sulfuric acid solution Solutions Part 2 Units of concentration by mass g solute g solution x 100 ppm g solute g solution x 106 or g solute 106 g solution or 1 ppm 1 mg solute L solution Note ppm units are usually used for very dilute solutions where the density is 1 00 g mL or g solute 100 g solution Molarity M moles solute L solution Normality N equivalents L Normality is a unit used mostly for acids or bases to emphasize the amount of available H or OH in solution whether ionized or not A 0 5 M solution of HCl is 0 5 N A 0 5 M solution of H2SO4 is 1 0 N A 0 5 M solution of Ca OH 2 is 1 0 N pH log H The bracket refers to the molarity of an individual ion or molecule such as the hydrogen ion Actually in water H is H3O the hydronium ion but for convenience we usually just refer to it as H pOH log OH pH pOH 14 0 at pH 7 the H and OH are equal A strong acid such as HCl is completely dissociated in water thus in a 0 01 M solution of HCl H 0 01 M and Cl 0 01 M and the pH would be log 0 01 2 A weak acid such as HF may be about 10 dissociated so in a 0 01 M solution of HF the concentration of H would be 10 of 0 01 0 001 M so the pH 3 Problems 1 What is the molarity of a concentrated 37 0 hydrochloric acid solution given that the density of the solution is 1 11 g mL 2 What is the molar mass of a weak acid given that 1 00 g of the acid reacts in a 1 1 mole ratio with 25 0 mL of 0 200 M KOH 3 What is the pH of a 0 020 M weak acid solution which is 5 0 dissociated 4 A dilute solution of HCl has a pH of 4 0 What is the molarity of the HCl 5 In any aqueous solution pH pOH 14 0 What is the pH of a 0 0010 M solution of NaOH 6 Optional Using pH indicator paper if available test the pH of various common liquids such as vinegar soda milk Windex other cleaning solutions