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Transcript of 1 Solutions stry/flash/molvie1.swf PropertiesOfSolutions/Colligative.html.
1
SolutionsSolutions
http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/molvie1.swf
http://www.chemistryland.com/CHM151W/11-PropertiesOfSolutions/Colligative.html
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• I stored sodas in a small refrigerator. One day I noticed that the Diet Coke had exploded from freezing but the regular Coke did not freeze and therefore did not explode.
• I thought why did the Diet Coke freeze and not regular Coke?
• Regular coke has about 39 grams of sugar dissolved in it.
• The 39 grams of sugar interfered with the water trying to freeze. So the freezing point of regular Coke was lower than that of Diet Coke.
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DefinitionsDefinitions
A solution is a mixture of 2 or A solution is a mixture of 2 or more substances in a single more substances in a single phase. phase.
solute + solvent=> solutionsolute + solvent=> solution
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Parts of a Solution• SOLUTE – the
part of a solution that is being dissolved (less amount)
• SOLVENT – the part of a solution that dissolves the solute ( greater amount)
Solute Solvent Example
solid solid
solid liquid
gas liquid
gas gas
5Concentration of a Concentration of a SolutionSolution
Concentration of a Concentration of a SolutionSolution
The amount of solute in a solution is The amount of solute in a solution is given by its given by its concentrationconcentration, or , or molaritymolarity
M = n / V and n = m / MMM = n / V and n = m / MM
Molarity (M) = moles soluteliters of solution
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PROBLEM: PROBLEM: Dissolve 5.00 g of NiCl Dissolve 5.00 g of NiCl22 in in enough water to make 250 mL of solution. enough water to make 250 mL of solution. Calculate the Molarity.Calculate the Molarity.
PROBLEM: PROBLEM: Dissolve 5.00 g of NiCl Dissolve 5.00 g of NiCl22 in in enough water to make 250 mL of solution. enough water to make 250 mL of solution. Calculate the Molarity.Calculate the Molarity.
Step 1: Step 1: Calculate moles Calculate moles of NiClof NiCl22
Step 2: Step 2: Calculate MolarityCalculate Molarity
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USING MOLARITYUSING MOLARITYUSING MOLARITYUSING MOLARITY
What mass of oxalic acid, What mass of oxalic acid, HH22CC22OO44, is, is
required to make 580 mL of a 0.0500 Mrequired to make 580 mL of a 0.0500 Msolution?solution?
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Percent SolutionsDensity = mass / volume d H2O = 1g/ mL
1. Volume/Volume
When both solute and solvents are liquids.
Percent by volume( % v/v) = volume of solute x 100%
______________
volume of solution
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• What is the percent by volume of ethanol in the final solution when 85mL of ethanol is diluted with 250 mL of water?
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• A bottle of the antiseptic hydrogen peroxide, H2O2 is labeled 3.0 %(v/v). How many mL of hydrogen peroxide are in a 2 L bottle of this solution?
• What is the molarity?
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2. Mass / Mass
• When both solute and solvent are solids.
Percent by mass( % m/m) = mass of solute x 100%
______________
mass of solution
• How many grams of potassium sulfate are required to make 1500g of a 5% m/m solution?
• How much water?
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3. Mass/ Volume ( % m/v)
Percent ( % m/v) = mass of solute x 100%
_____________
volume of solution
18 g of ethanol dissolves in 400 mL of water. What is the concentration in % m/v ?
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Making Dilutions
M1 V1 = M2 V2
Where:M1 = concentration of the first solutionV1 = volume of the first solutionM2 = concentration of the second solutionV2 = volume of the second solution
Examples:
1.How many mililiters of a solution of 4M KI are needed to prepare 400 mL of a 0.76 M ?
2. How much water would I need to add to 500 mL of a 2.4 M KCl solution to make a 1.0 M solution?
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• 3) How much 0.05 M HCl solution can be made by diluting 250 mL of 10 M HCl?
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•
• 4) I have 345 mL of a 1.5 M NaCl solution. If 100 mL of water evaporates, what will the molarity of the solution be?
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• If I add 15g of CaCl2 to a flask and complete to a final volume of 500 mL,
• A) What is the % by mass?
• B) What is the molarity of the solution?
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Question 12
• If I make a solution by adding water to 35 mL of methanol until the final volume of the solution is 275 mL…
• a) What is the molarity of methanol in this solution? (The density ofmethanol is 0.792 g/mL)
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• http://instruct.westvalley.edu/harrison/chem30A/worksheets/soultionsworksheet.pdf