Presentation on theme: "Molarity = Molarity ( M ) moles solute liters of solution"— Presentation transcript:
1 Molarity = Molarity ( M ) moles solute liters of solution Molarity is defined as the amount of moles of a compound dissolved in an amount of solvent (usually water).It can be solved with the equation:Molarity(M)=moles soluteliters of solution
2 Molarity – What is it? A measure of how concentrated a solution is. Think about making Kool-Aid.What makes Kool-Aid more delicious?The more sugar you add, the sweeter the solution gets.Adding more moles of sugar, without changing the volume makes the Molarity “Concentration” Increase
3 Molarity Practice1) 80.5 grams of sodium chloride is dissolved in 3.5 Liters. Determine the Molarity.2) 125 grams of Calcium Fluoride is dissolved in 250 mL of water. Solve for the Molarity.
4 2.80 M = x mol / 0.500 L = 1.40 mol 1.40 mol 166 g KI 1 mol KI What mass of KI is required to make 500. mL ofa 2.80 M KI solution?2.80 M = x mol / L = 1.40 mol1.40 mol166 g KI1 mol KI= 232 g KI12.3
5 Dilution of SolutionsDilution is the procedure for preparing a less concentrated solution from a more concentrated solution.When you want to dilute a solution, what happens to the number of moles present in the solution?Do they increase?Decrease?Stay the same?Stay the same.5
6 Since moles are constant before and after dilution, we can use the following formula for dilution calculations.M1V1=M2V2M1 = Starting Molarity , V1 = Initial Volume of solutionM2 = Final Molarity, V2 = Final Volume of solution
7 ExampleDescribe how you would prepare 800mL of a 2.0M H2SO4 solution, starting with a 6.0 M stock solution.MiVi = MfVf6.0M x Vi = 2.0M x 0.800LVi = 1.6M x L/ 6.0MVi = 0.26LHow much water will need to be added?
8 How would you prepare 60.0 mL of 0.2 M HNO3 from a stock solution of 4.00 M HNO3?MiVi = MfVfMi = 4.00Mf = 0.200Vf = 0.06 LVi = ? LVi =MfVfMi=0.200 x 0.064.00= L = 3 mL3 mL of acid+ 57 mL of water= 60 mL of solution4.5
9 Solution Stoichiometry We use the same ideas when we converted from grams of one compound to grams of another, except we are in mL of solution instead of grams.Use the Molarity equation: M = mol/LUse stoichiometry to convert moles of one compound to moles of the other compound.X gramsX mol X gramsY molX molY gramsY mol
10 Solution Stoich Practice How many mL of 2.00 M Hydrobromic acid, when reacted with aluminum hydroxide, will be required to produce 60.0 grams of water in the acid base reaction?___HBr +___Al(OH)3 ___H2O + ___ AlBr3313160.0 g H2O1 mol H2O g H2O3 mol HBr 3 mol H2O= 3.33 mol HBr3.33 mol HBr2.00 M HBr == 1.67 mL HBrX ml HBr