260 likes | 682 Views
Molarity: The concentration of a solution. A solution is a mixture. The solute is the substance dissolved (Usually the substance that there is less of) The solvent is the substance that does the dissolving. Solute + Solvent = Solution. 1. What is the solvent in air?
E N D
A solution is a mixture • The solute is the substance dissolved (Usually the substance that there is less of) • The solvent is the substance that does the dissolving
Solute + Solvent = Solution 1. What is the solvent in air? A) Nitrogen B) oxygen C) carbon dioxide 2. What is the solvent in coca cola? • Sugar B) water C) carbon dioxide 3. What is an aqueous solution? • Dissolved in methane • Dissolved in water • Dissolved in petrol
Molarity (M) The molar concentration shows the number of moles of solute in one liter (dm3) of solution Molarity (M) = moles of solute 1 dm3 solution
Note: http://isterguch.brinkster.net
Molarity Calculations If 4.0 g NaOHare used to make 500. mL of NaOH solution, what is the molarity (M) of the solution?
If 4.0 g NaOH are used to make 500. mL of NaOH solution, what is the molarity (M) of the solution? Step 1 Find the moles (Divide by the molar mass) 4.0 g NaOH x 1 mole NaOH = 0.10 mole NaOH 40.0 g NaOH Step 2: convert to dm3 (Divide mL by 1000) 500. mL x 1 L _ = 0.500 L 1000 mL Step 3 Divide moles of solute by volume of solution 0.10 mole NaOH = 0.20 M 0.500 L
Molarity Calculation A KOH solution with a volume of 400 mL contains 2.0 mole KOH. What is the molarity of the solution? A) 8.0 M B) 5.0 M C) 2.0 M
A KOH solution with a volume of 400.0 mL contains 2.0 moles of KOH. What is the molarity of the solution? B) 5.0 M M = 2.0 mole KOH = 5.0 M 0.4 L
Calculation A glucose solution with a volume of 2.0 L contains 72.0 g glucose (C6H12O6). If glucose has a molar mass of 180.0 g/mole, what is the Molarity of the glucose solution? A) 0.20 M B) 5.0 M C) 36 M
A glucose solution with a volume of 2.0 L contains 72.0 g glucose (C6H12O6). What is the Molarity of the glucose solution? A) 72 g x 1 mole x 1 = 0.20 M 180. g 2.0 L
Molarity Conversion Factors A solution is a 3.0 M NaOH.. Write the molarity in the form of conversion factors. 3.0 moles NaOH or: 1 L NaOH soln 1 L NaOH soln 3.0 moles NaOH
Example Stomach acid is a 0.10 M HCl solution. How many moles of HCl are in 1500 mL of stomach acid solution? A) 15 moles HCl B) 1.5 moles HCl C) 0.15 moles HCl
Stomach acid is a 0.10 M HCl solution. How many moles of HCl are in 1500 mL of stomach acid solution? C) 1500 mL x 1 L = 1.5 L 1000 mL 1.5 L x 0.10 mole HCl = 0.15 mole HCl 1 L (Molarity factor)
Calculation How many grams of KCl are present in 2.5 L of 0.50 M KCl? A) 1.3 g B) 5.0 g C) 93 g
How many grams of KCl are present in 2.5 L of 0.50 M KCl? Answer C) 2.5 L x 0.50 mole x 74.6 g KCl = 93 g KCl 1 L 1 mole KCl
Calculate How many milliliters of stomach acid, which is 0.10 M HCl, contain 0.15 mole HCl? A) 150 mL B) 1500 mL C) 5000 mL
How many milliliters of stomach acid, which is 0.10 M HCl, contain 0.15 mole HCl? B) 0.15 mole HCl x 1 L soln x 1000 mL 0.10 mole HCl 1 L = 1500 mL HCl
Calculation How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution? A) 12 g B) 48 g C) 300 g
How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution? B) 400. mL x 1 L = 0.400 L 1000 mL 0.400 L x 3.0 mole NaOH x 40.0 g NaOH 1 L 1 mole NaOH = 48 g NaOH
Solution preparation • Weigh out a solid solute, pour into a volumetric flask and dissolve in the given quantity of solvent.
5.00 g of NiCl2•6 H2O are dissolved in enough water to make 250 mL of solution. The molar mass of Nickel(II) Chloride hexahydrate is 237.7 g/mol. Find the Molarity. • 0.0841 • 0.0000841 • 189 • 0.189 Answer: A