slide 1 of 39 chemistry 16.1. © copyright pearson prentice hall properties of solutions > slide...

of 39

Chemistry 16.1

© Copyright Pearson Prentice Hall

Properties of Solutions >

Slide 2 of 39

Solution Formation

Solution Formation

What factors determine the rate at which a substance dissolves?

16.1

of 39


Properties of Solutions >Solution Formation

The compositions of the solvent and the solute determine whether a substance will dissolve. The factors that determine how fast a substance dissolves are

• stirring (agitation)

• temperature

• the surface area of the dissolving particles

16.1

of 39



A cube of sugar in cold tea dissolves slowly.

16.1

of 39



Granulated sugar dissolves in cold water more quickly than a sugar cube, especially with stirring.

16.1

of 39



Granulated sugar dissolves very quickly in hot tea.

16.1

of 39



Stirring and Solution Formation

Stirring speeds up the dissolving process because fresh solvent (the water in tea) is continually brought into contact with the surface of the solute (sugar).

16.1

of 39



Temperature and Solution Formation

At higher temperatures, the kinetic energy of water molecules is greater than at lower temperatures, so they move faster. As a result, the solvent molecules collide with the surface of the sugar crystals more frequently and with more force.

16.1

of 39



Particle Size and Solution Formation

A spoonful of granulated sugar dissolves more quickly than a sugar cube because the smaller particles in granulated sugar expose a much greater surface area to the colliding water molecules.

16.1



Slide 10 of 39

Solubility

Solubility

How is solubility usually expressed?

16.1

of 39


Properties of Solutions >Solubility

A saturated solution contains the maximum amount of solute for a given quantity of solvent at a given temperature and pressure.

An unsaturated solution contains less solute than a saturated solution at a given temperature and pressure.

16.1

of 39



In a saturated solution, the rate of dissolving equals the rate of crystallization, so the total amount of dissolved solute remains constant.

16.1

of 39



The solubility of a substance is the amount of solute that dissolves in a given quantity of a solvent at a specified temperature and pressure to produce a saturated solution.

Solubility is often expressed in grams of solute per 100 g of solvent.

16.1

of 39



Some liquids combine in all proportions, while others don’t mix at all.

• Two liquids are miscible if they dissolve in each other in all proportions.

• Two liquids are immiscible if they are insoluble in each other.

16.1

of 39



Oil and water are immiscible.

16.1



Slide 16 of 39

Factors Affecting Solubility


What conditions determine the amount of solute that will dissolve in a given solvent?

16.1



Slide 17 of 39


Temperature affects the solubility of solid, liquid, and gaseous solutes in a solvent; both temperature and pressure affect the solubility of gaseous solutes.

16.1

of 39


Properties of Solutions >Factors Affecting Solubility

Temperature

• The solubility of most solid substances increases as the temperature of the solvent increases.

• The solubilities of most gases are greater in cold water than in hot.

16.1

of 39


Properties of Solutions >Factors Affecting Solubility16.1

of 39



A supersaturated solution contains more solute than it can theoretically hold at a given temperature.

The crystallization of a supersaturated solution can be initiated if a very small crystal, called a seed crystal, of the solute is added.

16.1

of 39



A supersaturated solution is clear before a seed crystal is added.

16.1

of 39



Crystals begin to form in the solution immediately after the addition of a seed crystal.

16.1

of 39



Excess solute crystallizes rapidly.

16.1

of 39


Properties of Solutions >Factors Affecting Solubility16.1

of 39



Pressure

Changes in pressure have little effect on the solubility of solids and liquids, but pressure strongly influences the solubility of gases.

Gas solubility increases as the partial pressure of the gas above the solution increases.

16.1


Slide 26 of 39

16.1 Section Quiz.

1. For a given substance, which of the following will NOT influence how fast it dissolves?

a. temperature

b. amount of agitation

c. molar mass

d. size of the crystals


Slide 27 of 39

16.1 Section Quiz.

2. The solubility of a substance is often expressed as the number of grams of solute per

a. 100 liters of solvent.

b. 1 cm3 of solvent.

c. 100 grams of solution.

d. 100 grams of solvent.


Slide 28 of 39

16.1 Section Quiz.

3. The solubility of a gas in a solvent is affected by

a. both temperature and pressure.

b. only pressure.

c. only temperature.

d. both pressure and agitation.


Slide 29 of 39

16.2Molarity

Molarity

How do you calculate the molarity of a solution?


Slide 30 of 39

Molarity

a. The concentration of a solution is a measure of the amount of solute that is dissolved in a given quantity of solvent.

A dilute solution is one that contains a small amount of solute.

A concentrated solution contains a large amount of solute.

16.2


Slide 31 of 39

Molarity

a.Molarity (M) is the number of moles of solute dissolved in one liter of solution.

b.To calculate the molarity of a solution, divide the moles of solute by the volume of the solution.

16.2


Slide 32 of 39

Molarity

a. To make a 0.5-molar (0.5M) solution, first add 0.5 mol of solute to a 1-L volumetric flask half filled with distilled water.

16.2


Slide 33 of 39

Molarity

a. Swirl the flask carefully to dissolve the solute.

16.2


Slide 34 of 39

Molarity

a. Fill the flask with water exactly to the 1-L mark.

16.2


Slide 35 of 39

16.2


Slide 36 of 39

16.2


Slide 37 of 39

16.2


Slide 38 of 39

16.2


Slide 39 of 39

Problem Solving 16.8 Solve Problem 8 with the help of an interactive guided tutorial.

for Sample Problem 16.2


Slide 40 of 39

16.3


Slide 41 of 39

Sample Problem 16.3

16.3


Slide 42 of 39

Sample Problem 16.316.3


Slide 43 of 39

Sample Problem 16.316.3


Slide 44 of 39



Slide 45 of 39

16.2Making Dilutions

Making Dilutions

What effect does dilution have on the total moles of solute in a solution?


Slide 46 of 39

Making Dilutions

Diluting a solution reduces the number of moles of solute per unit volume, but the total number of moles of solute in solution does not change.

16.2


Slide 47 of 39

Making Dilutions

a. The total number of moles of solute remains unchanged upon dilution, so you can write this equation.

a. M1 and V1 are the molarity and volume of the initial solution, and M2 and V2 are the molarity and volume of the diluted solution.

16.2


Slide 48 of 39

Making Dilutions

a. Making a Dilute Solution

16.2


Slide 49 of 39

Making Dilutions

a. To prepare 100 ml of 0.40M MgSO4 from a stock solution of 2.0M MgSO4, a student first measures 20 mL of the stock solution with a 20-mL pipet.

16.2


Slide 50 of 39

Making Dilutions

a. She then transfers the 20 mL to a 100-mL volumetric flask.

16.2


Slide 51 of 39

Making Dilutions

a. Finally she carefully adds water to the mark to make 100 mL of solution.

16.2


Slide 52 of 39

Making Dilutions

a. Volume-Measuring Devices

16.2


Slide 53 of 39

16.4


Slide 54 of 39

16.4


Slide 55 of 39

16.4


Slide 56 of 39

16.4


Slide 57 of 39


`


Slide 58 of 39

Percent Solutions

Percent Solutions

What are two ways to express the percent concentration of a solution?

16.2


Slide 59 of 39

Percent Solutions

The concentration of a solution in percent can be expressed in two ways: as the ratio of the volume of the solute to the volume of the solution or as the ratio of the mass of the solute to the mass of the solution.

16.2


Slide 60 of 39

Percent Solutions

Concentration in Percent (Volume/Volume)

16.2


Slide 61 of 39

Percent Solutions

a. Isopropyl alcohol (2-propanol) is sold as a 91% solution. This solution consist of 91 mL of isopropyl alcohol mixed with enough water to make 100 mL of solution.

16.2


Slide 62 of 39

16.5


Slide 63 of 39

16.5


Slide 64 of 39

16.5


Slide 65 of 39

16.5


Slide 66 of 39

Practice Problems For Sample Problem 16.5

Problem-Solving 16.15 Solve Problem 15 with the help of an interactive guided tutorial.



Slide 67 of 39

Percent Solutions

Concentration in Percent (Mass/Mass)

16.2


Slide 68 of 39

16.2 Section Quiz.

16.2.


Slide 69 of 39

16.2 Section Quiz.

1. To make a 1.00M aqueous solution of NaCl, 58.4 g of NaCl are dissolved in

a. 1.00 liter of water.

b. enough water to make 1.00 liter of solution

c. 1.00 kg of water.

d. 100 mL of water.


Slide 70 of 39

16.2 Section Quiz.

2. What mass of sodium iodide (NaI) is contained in 250 mL of a 0.500M solution?

a. 150 g

b. 75.0 g

c. 18.7 g

d. 0.50 g


Slide 71 of 39

16.2 Section Quiz.

3. Diluting a solution does NOT change which of the following?

a. concentration

b. volume

c. milliliters of solvent

d. moles of solute


Slide 72 of 39

16.2 Section Quiz.

4. In a 2000 g solution of glucose that is labeled 5.0% (m/m), the mass of water is

a. 2000 g.

b. 100 g.

c. 1995 g.

d. 1900 g.

slide 1 of 39 chemistry 16.1. © copyright pearson prentice hall properties of solutions > slide...

Documents

unsaturated solution

solute sugar

cube of sugar

sugar cube

substance dissolves

sugar crystals

given temperature

solvent molecules