starter s-160 define a.saturated solution b.miscible c.supersaturated solution

Starter S-160

Define

A. Saturated solution

B. Miscible

C. Supersaturated solution

Solutions

Chapter 16

16.1 Properties of Solutions

Chapter 16

Solutions occur when a solute dissolves in a solvent

Solutions are homogeneous mixtures

Three factors determine how rapidly solutes dissolve

16.1 Solution Properties

Sink Hole

Animation

http://www.msnbc.msn.com/id/24531049/

http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/molvie1.swf

1. Stirring – moves fresh solvent over the surface of the solute

2. Temperature – particles move faster at higher temperatures, increase in frequency and force of collisions between solute and solvent

3. Particle Size – smaller particles expose greater surface areas to the colliding solvent


Solubility – the amount of solute dissolved in a given amount of solvent

Unsaturated – more

solute can be

dissolved at a

specific temp

Saturated – maximum

solute that can

be dissolved


Some liquids are infinitely soluble in each other.

They are said to be miscible.

Immiscible – liquids that are insoluble in each other

Solubility is often given as

grams of solute per 100g of

solvent


immiscible

http://www.teachertube.com/viewVideo.php?video_id=79810&title=Richard_Garriott_Space_Blog_Mixing_of_Liquids

A solubility curve gives the solubility (usually in grams solute per 100g solution) as it varies with temperature

For most substances solubility increases with temperature

Charts are for specific solvents

You will need to read these charts for the test


Pressure has little effect on the solubility of liquids or solids

Strong effect on the solubility of gases

Henry’s Law – at a certain

temperature, the

solubility of a gas in

a liquid is proportional

to the pressure of the

gas above the liquid


2

2

1

1

P

S

P

S

Starter S-162

Using the chart that will show up in a second,

A. What is the solubility of sodium nitrate at 70oC?

B. How much Potassium Iodide could be dissolved in 400g of water at 10oC?

C. A saturated solution of NH3 is heated from 20oC to 60oC, how much ammonia precipitates out?

16.2 Concentrations of Solutions

Chapter 16

There are different ways to calculate how much solute is dissolved

Concentration – the amount of solute dissolved in a solvent

Dilute – small amount

of solute

Concentrated – large

amount of solute


Molarity (M) – the number of moles of solute dissolved in one liter of solution

Moles are calculated from the mass

Volume must be in liters (convert from mL if necessary)

Volume is the total final volume of the solution, not the volume of the solvent


V

nM

Example: 0.90g NaCl is dissolved to make 100.0 mL of solution. What is the molarity of the soution?


V

nM

gggmassmolar 5.58)5.35()0.23(.

molg

molgNaCln 0154.0

5.58

190.0

V

molM

0154.0

LmL

LmLV 1000.0

1000

10.100

L

molM

1000.0

0154.0 MM 15.0

Example: Household laundry bleach is a dilute aqueous solution of sodium hypochlorite. How many moles of solute are present in 1.5 L of 0.70M NaClO?


V

nM MVn )5.1)(70(. LMn moln 05.1 moln 0.1

Often it is necessary to dilute a chemical.

Make it’s molarity lower

However, we can not reduce the number of moles in solution without a chemical reaction


V

nM MVn 2211 VMnVM 2211 VMVM

Example: How many milliliters of aqueous 2.00M Magnesium Sulfate must be diluted with water to prepare 100.0 mL of 0.400 M Mangesium Sulfate?

This means that 20.0 mL of the 2.00 M solution must be mixed with 80.0 mL of water (the solvent) to make the 0.400 M solution


)0.100)(400.0()00.2( 1 mLMVM 2211 VMVM mLV 0.201

Percent Solutions – can be expressed two ways

Percent by mass


%100.

.% x

solutionmass

solutemassm

Example: How many grams of glucose is needed to make 2000.0g of a 2.8% by mass solution?


%100.

.% x

solutionmass

solutemassm %100

0.2000

.%8.2 x

g

solutemass

g

solutemass

0.2000

.028.0 gsolutemass 56.

Percent by volume

It helps often to remember that 1g of water equals 1 mL of water


%100.

.% x

solutionvolume

solutevolumeV

Example: What is the percent volume of ethanol (C2H6O) in the final solution when 85 mL of ethanol is diluted by adding 165 mL of water?


%100.

.% x

solutionvolume

solutevolumeV %100

)16585(

)85(% x

mLmL

mLV

%100)250(

)85(% x

mL

mLV %10034.0% xV %34% V

Starter S-164

18.2 g of H2SO4 are dissolved to make a 1.3 M solution. What is the final volume of the solution?

16.3 Colligative Properties of Solutions

Chapter 16

Colligative Property – depends only on the number of solute particles, not their identity

1. Vapor-Pressure Depression (lowering)

2. Boiling-Point Elevation (increasing)

3. Freezing-Point Depression


Vapor-Pressure Depression

The surface of a liquid has particles that are constantly leaving the surface and some particles returning (equilibrium)



If a solute is dissolved in the solvent

Not as many molecules can escape the surface



This reduces the amount of gas above the solution

So the vapor pressure decreases



The decrease in a solution’s vapor pressure is proportional to the number of particles the solute makes in solution


Freezing-Point Depression

When a substance freezes the particles take on an orderly pattern

The addition of a solute

disrupts this pattern

More kinetic energy must be

withdrawn form the

solution to cause it to solidify



The difference in temperature between the normal freezing point of the solvent and the freezing point of the solution is called freezing-point depression



Salt is added to ice to lower the freezing point

If enough salt it added, the freezing point is depressed and the ice turns to liquid


Boiling Point Elevation

Boiling occurs when the vapor pressure of the liquid equals the atmospheric pressure

Solutes decrease vapor pressure, so a solution must be at a higher temperature before it can boil


Boiling Point Elevation

The difference between the normal boiling point of the solvent and the boiling point of the solution is called boiling point elevation


Remember that all colligative properties are proportional to the number of particles in solution

The greatest effect would occur in a 50/50 solutions

Antifreeze is mixed withwater to increasethe boiling point andto lower the freezingpoint


Starter S-165

What is the percent by mass if 12.0 g of sodium chloride is dissolved in 52 mL of water?

What is the percent by volume if 41 mL of sulfuric acid is dissolved in 202 mL of water?

Starter S-167

Test Day!

starter s-160 define a.saturated solution b.miscible c.supersaturated solution

Documents

g solution

solution propertiespressure

solution propertiessolubility

moles of solute

grams of solute

grams solute

solute dissolves

solution propertiesstarter