Unit A: Mix and Flow of Matter

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1 Unit A: Mix and Flow of Matter Science 8 1 Section 2.0 THE PROPERTIES OF MIXTURES AND FLUIDS CAN BE EXPLAINED BY THE PARTICLE MODEL OF MATTER. 2 1

2 Pure Substances and Mixtures Topic Matter Classification Matter Pure Substances Mechanical Mixtures Mixtures Solutions Suspensions and Colloids 4 2

Matter All matter is either a pure substance or a.

unique set of characteristics or properties.

Example: sugar, distilled water, aluminum foil, baking soda A

ent.e. Each substance keeps its properties, but it may be

Mechanical Mixtures In a mechanical mixture, you can see the

3 Matter All matter is either a pure substance or a. A pure substance is made up of only one kind of matter and has a unique set of characteristics or properties. You cannot separate them into different substances. Example: sugar, distilled water, aluminum foil, baking soda A mixture is made up of a combination of different.e. Each substance keeps its properties, but it may be difficult to identify these properties. Example: soil, soda pop (sugar!!), mixed vegetables 5 Mechanical Mixtures and Solutions Mechanical Mixtures In a mechanical mixture, you can see the different substances that make up the mixture. Also known as a heterogeneous mixture. Example: Homogeneous Mixtures In other mixtures, you can t see the different substances that make them up. These mixtures may be: solutions (i.e. vinegar), suspensions, or colloids. A solution looks as if it is all one substance and is called a homogenous mixture 6 3

Example: tomato juice, muddy water Colloids A cloudy mixture but the droplets or tiny pieces are so small that they do not separate out

4 Suspensions and Colloids Suspensions A suspension is a cloudy mixture in which droplets or tiny pieces of one substance are held within another substance. If you leave suspension undisturbed, its parts will usually separate out. Example: tomato juice, muddy water Colloids A cloudy mixture but the droplets or tiny pieces are so small that they do not separate out easily. Example: homogenized milk is a colloid of tiny cream droplets in whey. 7 Matter Classification Matter Pure Substances Mechanical Mixtures Mixtures Solutions Suspensions and Colloids 8 4

If the fluid is a pure substance, it will move up a strip of filter paper to one level.

5 Paper Chromatography The paper chromatography test can be used to determine if a substance is a pure substance or a solution. A solution is added near the bottom of a piece of filter paper and placed partly in a solution. If the fluid is a pure substance, it will move up a strip of filter paper to one level. If the fluid is a solution, the different substances in it will move up the paper to different levels. 9 Paper Chromatography The filter paper used to test the substance is called a The distance a substance moves depends on its attraction to the paper. Those with the strongest attraction to the paper don t move very far while those with the weakest attraction move farthest. 10 5

6 Homework! Check and Reflect Page 23 # 1, 2 11 Concentration and Solubility Topic

Solutions into another makes a solution.

dissolving is called the In a concentrated solution, there are amounts of

Example: making orange juice from frozen juice concentrate by mixing the

concentration of a solution tells you Example: a solution with 50 g of

7 Solutions into another makes a solution. The substance that dissolves is called the The substance that does the dissolving is called the In a concentrated solution, there are amounts of solute in the solvent. Example: making orange juice from frozen juice concentrate by mixing the orange solid concentrate ( ) in a small amount of water ( ). You add water to make a. A diluted solution has small amounts of solute in the solvent. 13 Measuring Concentration The concentration of a solution tells you Example: a solution with 50 g of solute dissolved in 100 ml of water has a concentration of 50 g/100 ml of water. This is read as fifty grams per one hundred millilitres. Sometimes, you will see concentration stated in other ways. Example: Example: 14 7

Example: Compare two salt water solutions, one with a concentration of 25 g/100 ml compared to one

8 Comparing Concentrations To compare the concentrations of two solutions, you need to know the amount of solute in the same volume of solvent for each solution. Example: Compare two salt water solutions, one with a concentration of 25 g/100 ml compared to one at 50 g/100 ml. 15 Unsaturated Solutions As long as the solute keeps dissolving (i.e juice crystals), you have an unsaturated solution. 16 8

9 Saturated Solutions is the maximum amount of solute you can add to a fixed volume of solvent at a given temperature. A solution s at a given temperature is the point at which no more solute can be dissolved in a fixed volume of solvent at that temperature. 17 Homework! Check and Reflect Page 28 # 1, 2, 3, 4,

10 Factors Affecting Solubility Topic Solubility Solubility depends on at least three factors: 20 10

If you see the term, that means the solvent is water.

11 Types of Solutes and Solvents The most common solvent is, which is commonly referred to as the because it can dissolve so many different substances. If you see the term, that means the solvent is water. (Aqua is the Latin word for water.) 21 Temperature For most solid or liquid substances, As the temperature increases, 22 11

Thermal Pollution Water from a lake or river is commonly used

Once the water is used, it is warmer than when it was taken

Before it can be returned to the lake or river, it must be

What would happen if the warm water were poured directly back

12 Thermal Pollution Water from a lake or river is commonly used in industrial plants as a coolant. Once the water is used, it is warmer than when it was taken into the plant. Before it can be returned to the lake or river, it must be stored in a cooling pond. What would happen if the warm water were poured directly back into the river or lake? This is commonly called Keep in mind that the solubility of oxygen is less in warmer water. 23 Homework! Check and Reflect Page 31 # 1, 2,

13 The Particle Model of Matter and the Behaviour of Mixtures Topic The Particle Model of Matter The particle model of matter has four main points that describe the structure of matter. 1. All matter is made up of 2. The tiny particles of matter are always moving and vibrating. i. For solids, this movement is like ii. For liquids, the particles are and over each other. iii. For gases, this movement means moving 3. The particles in matter may be to each other or together. 4. The particles have between them. Notice the difference in the amount of space between particles of a solid and a gas

14 A Closer Look at the Particles 27 Mixing Substances When two different substances are mixed together, the smaller particles of one substance fill in the spaces between the larger particles of the other

Dissolving The particle model can also explain why substances dissolve. The particle model states that particles are attracted to each other.

For example, when salt is placed in water, its particles are attracted to the water particles. This is the process called dissolving.

This is why a solute seems to disappear when mixed with a solvent.

15 Dissolving The particle model can also explain why substances dissolve. The particle model states that particles are attracted to each other. However, particles in some substances are more attracted to particles in other substances than to each other. For example, when salt is placed in water, its particles are attracted to the water particles. This is the process called dissolving. In a solution, the particles of the solute (salt) are attracted to the particles of the solvent (water). The solute dissolves in the solvent. This is why a solute seems to disappear when mixed with a solvent. 29 Factors Affecting the Rate of Dissolving: (1) Temperature How fast will a solute dissolve in a solvent? How can you make a solute dissolve more quickly? Heat energy is transferred by the movement of the particles. Because the solvent particles are moving faster, they bump into the solute particles faster

All the smaller pieces together have more surface area among them for the solvent particles to bump into. Think of cooking a potato in water.

16 Factors Affecting the Rate of Dissolving: (2) Size of Pieces How fast will a solute dissolve in a solvent? How can you make a solute dissolve more quickly? All the smaller pieces together have more surface area among them for the solvent particles to bump into. Think of cooking a potato in water. If you put the whole potato in, it takes a long time to cook. If you cut the potato up into smaller pieces, the cooking time becomes much shorter. 31 Factors Affecting the Rate of Dissolving: (3) Stirring How fast will a solute dissolve in a solvent? How can you make a solute dissolve more quickly? 32 16

17 Homework! Check and Reflect Page 36 # 2, 4 Section Review Page 37 # 1, 3, 4,

How can homogeneous and heterogeneous mixtures be. 1. classified? 2. separated?

How can homogeneous and heterogeneous mixtures be 1. classified? 2. separated? 1. HETEROGENEOUS MIXTURE 2. COLLOID 3. EMULSION 4. SUSPENSION 5. FILTRATION 6. TYNDALL EFFECT 7. HOMOGENEOUS MIXTURE 8. SOLUTION