solutions (chapter 12) taylor, tommy, kayla. homogeneous mixture - mixture of two or more substances...
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Solutions (Chapter 12)
Taylor, Tommy, Kayla
Homogeneous mixture - mixture of two or more substances that has a uniform appearance throughout ex: salt water
Heterogeneous mixture - can be separated physically and the different components are visibly distinguishable from one another
ex: chocolate chip cookie
http://merryann12.hubpages.com/hub/Heterogeneous-and-Homogeneous-Mixtures
Solute - substance being dissolved ex: Kool-Aid mix
Solvent - dissolves another substance ex: water
Solution - a homogeneous mixture of two or more substances.ex: Kool-Aid
https://www.google.com/search?q=kool+aid&oe=utf-8&aq=t&
http://www.chem4kids.com/files/matter_solution.html
Visual
Salt/ Solute
Water/ Solvent
Salt Water/ Solution
google.com
Suspension - a mixture in which large particles can be evenly distributed and the components will settle out
ex: muddy water
Colloid - a mixture in which small particles can be mixed so they remain evenly distributed without settling out ex: milk
http://www.800mainstreet.com/9/0009-001-mix-solut.html
Dilute - a solution containing a relatively small quantity of solute as compared with the amount of solvent ex: bleach
Concentrated - a solution that contains a large amount of solute relative to the amount that could dissolve ex: alcohol
http://www2.ucdsb.on.ca/tiss/stretton/chem2/acid02.html
Unsaturated - the solute concentration is lower than its equilibrium solubility
Saturated - a point of maximum concentration in which no more solute can be dissolved
Supersaturated - increase of concentration beyond saturation
http://shikagami21.blogspot.com/2007/08/saturated-unsaturated-and.html
Solubility Curves
Solute below the line indicates the solutionis unsaturated at a certain temperature
Solute above the line shows all of the solute has dissolved and is supersaturated
If the amount of solute is on line then the solution is saturated
Ex: At 500C and 100g, NaNo3 is saturated
At 200C and 100g, NaNo3 is supersaturated
At 200C and 50g, NaNo3 is unsaturated
http://gcserevision101.files.wordpress.com/2009/02/solubility-curves.jpg
Stirring A Solution
Stirring a solution helps disperse the solute particles and bring fresh solvent into contact with the solute surface. This increases the contact between the solvent and solute.
google.com
Surface Area
• The dissolution process occurs at the surface of the solute, so the larger the surface area of the solute the faster it dissolves.
google.com
Temperature of a Solution
• As the temp. of a solvent increases the solvent molecules move faster. This causes collisions between the solvent and solute molecules. This helps separate solute molecules and disperse them among the solvent molecules.
google.com
Concentration
When you increase the concentration of the solute, the rate of solution formation will also increase. They are directly related.
Molarity
The concentration of a solution expressed as the number of moles of solute dissolved in each liter of solution
moles of solute ormoles
Molarity= Liters of solutionL
Molarity CalculationsA saline (salt water) solution contains
0.70 g of NaCl per 100 ml of solution. What is its molarity?
First calculate the number of moles NaCl in the solution. You must use dimensional analysis to convert from grams to moles.
0.70 g NaCl x 1 mole NaCl = 0.01 mole
58.44 g NaCl
Molarity CalculationsWhere do the numbers come from?
0.70 g NaCl x 1 mole NaCl = 0.01 mol
58.44 g NaCl
Grams of solute given in problem
Formula mass of NaCl from periodic table
Formula mass correlates with grams in one mole
Molarity Calculations
Now that you have obtained the number of moles solute, use this number in the molarity equation:
M= 0.01 moles NaCl0.1L
To find this value, convert from ml (given in the problem) to liters.
M= 0.1
Molarity Practice
1. How many grams of CaCl2 are needed to make 125 ml of a 1.5 M solution of CaCl2?
2. How many moles of solute are present in 750 ml of a 0.10 M Na2SO4 solution?
Molarity Answers
1. How many grams of CaCl2 are needed to make 125 ml of a 1.5 M solution of CaCl2?
1.5M = moles of solute.125 L
.188 mol x 110.98 g CaCl2 = 20.9 g 1 mole CaCl2
Molarity Answers
2. How many moles of solute are present in 750 ml of a 0.10 M Na2SO4 solution?
.10 M = moles of solute = .075 moles .750 L Na2SO4
Molality
The number of moles of solute dissolved in each kilogram of solvent
moles of soluteor moles
Molality= Kilograms of solvent Kg
Molality is represented by "m "
Example Molality Problem:
What is the molality of a solution if 100 g of NaCl is dissolved into 250 g of water?
First calculate the number of moles NaCl in the solution. You must use dimensional analysis to convert from grams to moles.
100g NaCl x 1 mole NaCl = 1.71 moles NaCl
58.44g NaCl
Molality CalculationsWhere do the numbers come from?
100g NaCl x 1 mole NaCl = 1.71 mol NaCl
58.44g NaCl
Grams of solute given in problem
Formula mass of NaCl from the periodic table
Formula mass correlates with grams in one mole
Molality CalculationsNow that you have obtained the
number of moles solute, use this number in the molality equation:
m = 1.71 moles NaCl.25 Kg
m = 6.84
To find this value, convert from g (given in the problem) to Kg.
Molality Practice1. A solution was prepared by
dissolving 8.55 g of sucrose (table sugar, C12H22011) in 62.5 g of water. Find the molality of this solution.
2. A solution of iodine, I2, in carbon tetrachloride,CCl4, is used when iodine is needed for certain chemical tests. How much iodine must be added to prepare a 0.240 m solution of iodine in CCl4 if 50.0 g of CCl4 is used?
Molality Answers
1. A solution was prepared by dissolving 8.55 g of sucrose (table sugar, C12H22011) in 62.5 g of water. Find the molality of this solution.
8.55g C12H22011 x 1 mol C12H22011 = 0.0250 mol C12H22011
342.34 g C12H22011
m = 0.0250 mol C12H22011 = 0.400 m C12H22011
0.0625 kg H2O
Molality Answers2. A solution of iodine, I2, in carbon
tetrachloride,CCl4, is used when iodine is needed for certain chemical tests. How much iodine must be added to prepare a 0.240 m solution of iodine in CCl4 if 50.0 g of CCl4 is used?
50.0 g CCl4 x 1 kg = 0.05 kg CCl4
1000 g CCl4 0.240 m = X X= 0.012 moles I2
0.05 kg CCl40.012 moles I2 x 253.8 g I2 = 3.05 g I2
1 mole I2
Dilution
The concentration of a solution can be decreased by adding water.
M1 x V1 = M2 x V2
Original molarity
Original volume
Molarity after dilution
Volume after dilution
Volume should always be expressed in liters
Dilution Equation:
Dilution Calculations
How much concentrated 6.0 M hydrochloric acid is needed to prepare 50.0 ml of a 1.0 M solution?
First use the information given in the question in order to substitute into the dilution equation.
6.0 M x V1 = 1.0 M x 0.05 L
Dilution Calculations
Now, solve for the missing value algebraically.
6.0 M x V1 = 1.0 M x 0.05 L6.0V1 = 0.05
6.0 6.0 V1 = 0.0083
L
Dilution Practice
1. To what volume should 8.3 ml of 5.0 M nitric acid be diluted to prepare a 1.0 M solution?
2. To how much water should 12.5 ml of 3.0 M hydrochloric acid be added to produce a 1.0 M solution?
Dilution Answers
1. To what volume should 8.3 ml of 5.0 M nitric acid be diluted to prepare a 1.0 M solution?
5.0 M x 0.0083 L = 1.0 M x V2 0.0415 = 1.0V2
1.0 1.0V2= 0.042
L
Dilution Answers2. To how much water should 12.5 ml
of 3.0 M hydrochloric acid be added to produce a 1.0 M solution?
3.0 M x 0.0125 L = 1.0 M x V2
0.0375 = 1.0V2
1.0 1.0
V2 = 0.038 L
0.038 L - 0.0125 L = 0.026 L of H2O
Further Explanation2. To how much water should 12.5 ml
of 3.0 M hydrochloric acid be added to produce a 1.0 M solution?
3.0 M x 0.0125 L = 1.0 M x V2
Molarity of solute given in problem
Volume of solute given in problem
Final solute molarity given in problem
Unknown
2. To how much water should 12.5 ml of 3.0 M hydrochloric acid be added to produce a 1.0 M solution?
3.0 M x 0.0125 L = 1.0 M x V2
0.0375 = 1.0V2
1.0 1.0
V2 = 0.038 L
Further Explanation
Solve algebraically
3.0 M x 0.0125 L = 1.0 M x V2
0.0375 = 1.0V2
1.0 1.0
V2 = 0.038 L
0.038 L - 0.0125 L = 0.026 L of H2O
Further Explanation
Subtract the final volume and the original volume