Matter and Mixtures

Topic : Mixing and Dissolving

Mixing and Dissolving

All pure substances have their own unique set of properties, or characteristics.

All mixtures contain two or more pure substances, which have their own distinct properties (some of which may be hidden)

Classification of Matter

Homogenous Mixtures

- are mixtures which look as though they have only one set of properties.

- the blended mixture has equal amounts of both substances (all parts of the mixture are the same)

- if the homogenous mixture does not have any settling of any of the substances it is made of, then it is called a solutionsolution

- solutions occur because each particle slips between each other particle and is evenly distributed throughout the entire mixture

Heterogeneous mixture

Classification of: -in which the particles settle slowly after mixing, is

called a suspensionsuspension (eg. orange juice) - a heterogeneous mixture, in which the particles

do not settle at all, is called a colloidcolloid (eg. fog) - to disperse the particles for a longer period of time,

an emulsifying agent (like a protein) is used to form an emulsionemulsion (eg. mayonnaise)

- mixtures that are obviously two or more substances are called mechanical mixturesmechanical mixtures

-the separate parts of the mechanical mixture are called phases

What Makes Materials Dissolve?

- forming a solution by mixing two or more materials together is called dissolving

- dissolving occurs because of the attraction between the particles (there may be a stronger attraction to the particles of another substance, than to the particles of the same substance)

Using the particle theory explain how a Using the particle theory explain how a substance dissolves? substance dissolves?

Why does Salt dissolve in water?

The salt molecules have a strong attraction to the water molecules so the salt dissolves and forms a solution.

The water is the solvent (part of the solution that does the dissolving)

The Salt is the solute (part of the solution that is dissolved)

Solutes and Solvents

The solute is the substance that dissolves in a solvent. The solvent is the substance that dissolves

the solute to form a solution. SolubleSoluble means to be able to be dissolved in a

particular solvent. Solutes and solvents can be gases or liquids.

Identify: Solute and Solvent

Air

Pop

*20 K Gold jewelry

Steel

Salt water

Solvent-Nitrogen: Solute-Oxygen

Solvent-Water Solute-Sugar & CO2

Solvent-Gold Solute-Other metals

Solvent-Iron Solute-Other metals

Solvent-Water Solute-Salt

Water - the Universal Solvent

- it is called the 'universal solvent''universal solvent' because it can dissolve so many materials

97% of the water on Earth is Ocean water, 2% is frozen and only about 0.5% is 'usable' -and even this has materials already dissolved in it that can be harmful

The Rate of Dissolving

- the speed at which the solute dissolves in a solvent is called the rate of dissolvingrate of dissolving and can be affected by:

- agitation (stirring or shaking)

- temperature: increase of decrease

- pressure: increase of decrease

How Much Can Be Dissolved?

the limit to concentration is called solubility a saturated solution is one in which no more

solute will dissolve in a specific amount of solvent at a specific temperature

an unsaturated solution is one in which more solute can be dissolved in a specific solvent at the same specific temperature

- using the particle theory, SATURATION MEANSSATURATION MEANS the attractive forces between the particles

becomes balanced and no more particles of the solute can be attracted by the particles of the solvent

Beyond the Limit: Supersaturated Solutions a solution that contains more solute than

would normally dissolve at a certain temperature is called a super-saturated solution.

Cleaning Up with Solvents

Not all solutes will dissolve in solventsNot all solutes will dissolve in solvents. Insoluble means not able to be dissolved in a particular solvent.

- certain solvents are used for special circumstances because they will dissolve some solutes that water and other solvents cannot

What does it mean to be insoluble?What does it mean to be insoluble?

Cleaning Up with Solvents

(rubbing alcohol is use to dissolve chlorophyll - grass stains, because the particles have strong attractions)

Water will not dissolve oil or products that are oil based.

Mix an emulsifying agent with the water (phosphate based soap) and the oil will then dissolve when the clothes are washed.

Why will soap clean oil when it is added to Why will soap clean oil when it is added to water?water?

Topic:

Solutions and SolubilityAs well as

Percent Concentration

OR

WHAT DOES IT MEAN IF A SOLUTION IS SATURATED!

What is a solution?

Solution is homogeneous Composed of a solvent and a solute If a liquid solution the solvent is usually liquid

and the solute solid If it is a solution that is a solid solution like

Brass, the solvent is the greater quantity and the solute is the lesser quantity

Solubility

DEFn: The maximum amount of solute that can dissolve in a specific amount of solvent usually at a specific temperature.

g of solute

100 g water @ 200C

Saturated and Unsaturated

A saturated solution contains the maximum amount

of solute that can dissolve.

Undissolved solute remains.

An unsaturated solution does not contain all the

solute that could dissolve

Learning Check S1

At 40C, the solubility of KBr (Potassium Bromide) is 80

g/100 g H2O. Indicate if the following solutions are

(1) saturated or (2) unsaturated

A. ___60 g KBr in 100 g of water at 40C

B. ___200 g KBr in 200 g of water at 40C

C. ___25 KBr in 50 g of water at 40C

Solution S1

At 40C, the solubility of KBr is 80 g/100 g H2O.

Indicate if the following solutions are

(1) saturated or (2) unsaturated

A. 2 Less than 80 g/100 g H2O

B. 1 Same as 100 g KBr in 100 g of water

at 40C, which is greater than its solubility

C. 2 Same as 60 g KBr in 100 g of water,

which is less than its solubility

Temperature and Solubility of Solids

Temperature Solubility (g/100 g H2O)

KCl(s) NaNO3(s)

0° 27.6 74

20°C 34.0 88

50°C 42.6 114

100°C 57.6 182

The solubility of most solids (decreases or increases ) with an increase in the temperature.

Temperature and Solubility of Solids

Temperature Solubility (g/100 g H2O)

KCl(s) NaNO3(s)

0° 27.6 74

20°C 34.0 88

50°C 42.6 114

100°C 57.6 182

The solubility of most solids increases with an increase in the temperature.

Temperature and Solubility of Gases

Temperature Solubility (g/100 g H2O)

CO2(g) O2(g)

0°C 0.34 0.0070

20°C 0.17 0.0043

50°C 0.076 0.0026

The solubility of gases (decreases or increases) with an increase in temperature.

Temperature and Solubility of Gases

Temperature Solubility (g/100 g H2O)

CO2(g) O2(g)

0°C 0.34 0.0070

20°C 0.17 0.0043

50°C 0.076 0.0026

The solubility of gases decreases with an increase in temperature.

Learning Check S2

A. Why would a bottle of carbonated drink possibly

burst (explode) when it is left out in the hot sun ?

B. Why would fish die in water that gets too warm?

Solution S2

A. Gas in the bottle builds up as the gas becomes less soluble in water at high temperatures, which may cause the bottle to explode.

B. Because O2 gas is less soluble in warm water, the

fish may not obtain the needed amount of O2 for

their survival.