TEKS 5.5C The student knows that matter has measurable physical properties and those properties determine how matter is classified, changed and used. The student is expected to: (C) demonstrate that some mixtures maintain physical properties of their ingredients. (D) identify changes that occur in the physical properties of the ingredients of solutions such as dissolving salt in water or adding lemon juice to water.

What are some physical properties of matter?  Color  Texture  Odor  Conducts heat  Conducts electricity  Magnetic  Floats or sinks  Solubility  Boiling point  Melting point  Mass

Mixtures  Form when two or more substances combine  Keep their physical properties  Can be separated by their physical properties  Do not form a new substance

Salad is an example of a mixture  The lettuce and vegetables do not change when mixed

Is cereal a mixture? Yes…the properties of the substances do not change. You can still see the bananas, cereal, and milk.

Is cake a mixture? No…the properties of the substances change. The eggs, flour, and sugar change when the cake is mixed and baked.

Substances in a mixture can be separated by their physical properties…  Milk and cereal can be separated by pouring the mixture through a strainer.

The cereal would be trapped in the strainer and the milk would pass through.

QUESTION:  How could you separate a mixture of sand and sawdust?

ANSWER:  You can separate the sand from the sawdust by adding water. The sand will sink and the sawdust will float. Sawdust Water Sand

QUESTION:  Which scientific tool could you use to separate a mixture of iron filings and sand?

ANSWER:  You can separate the iron filings from the sand by using a magnet. Iron filings

Some students put two ice cubes on separate plates. One ice cube had a mass of 80 grams. The other had a mass of 40 grams. Which result would be the same for both ice cubes in this investigation? A The time it took each ice cube to melt completely B The temperature at which each ice cube melted C The amount of liquid produced on each plate D The total volumeof each ice cube

Some students were studying different types of mixtures. They stirred together one cup of oil and one cup of water in a large glass beaker. They observed that the water settled to the bottom and the oil floated to the top. Which of the following does this experiment demonstrate? A The oil completely mixed with the water. B The oil maintained its physical properties. C The oil caused the water to become more dense. D The oil melts in water

Solutions:

. 5.5 The student knows that matter has measurable physical properties and those properties determine how matter is classified, changed, and used. The student is expected to: (D) Identify changes that can occur in the physical properties of the ingredients of solutions such as dissolving salt in water or adding lemon juice to water.

Solutions are a special kind of mixture  One of the substances dissolves in another  The substance spreads out evenly  Solutions may be clear or colored  Can be separated using evaporation

dissolve – the process of a substance mixing with a liquid so evenly, that it breaks down in to invisible particles. Solubility-The ability of a substance to dissolve, not everything can dissolve with the same ease

Mixtures  2 or more substances  Each ingredient keeps its physical properties  Can separate easily, most case by hand (even if it takes forever) Solutions  2 or more substances  Involves dissolving a substance in another  Physical properties of the ingredients change  Can be separated, but usually requires heat/evaporation

Mixture of Water & Sugar The sugar dissolves into the water to form a solution.

 The hotter the liquid, the faster substances, such as sugar, salt, tea or coffee, will dissolve.  Solutions can be separated! Usually, solutions can be separated by letting the liquid part of the solution evaporate.

Which of these will dissolve and which will not? Make a Tree Map. Sugar Sand Salt Instant coffee Flour

Solution or Not dissolves does not dissolve Use the tree diagram above to list items that dissolve and items that do not dissolve from the website.

Solutions or Not dissolves does not dissolve Does your list look like this??? sugar salt instant coffee sand flour

* Test your knowledge about solutions by answering the next 4 questions

A. the water will now turn into a gas B. the sugar will dissolve into the water C. the water will dissolve into the sugar D. the two substances are chemically combining and chemically changing their properties 1. When the sugar and water in the beaker are combined, they will create a solution because -

B is the correct answer! Remember a solution is created when a solid is dissolved into a liquid. The sugar is being dissolved by the water. The sugar would not make the water change into a gas. Water does not dissolve into sugar. The substances in a solution do not change chemically and do not change their chemical properties.

2. When placed in a container full of water, which of the following would create a solution? A. sand B. pebbles C. pepper D. salt

The correct answer is D. Salt would dissolve into the water. Even though the salt particles are too tiny to see, they are still there. They have spread out evenly throughout the water. Sand, pebbles, and pepper would not dissolve into the water, and would therefore not create a solution. You would still be able to see them in the water and none of their properties would change.

3. Which of the following is an example of a solution? A. glass of Kool-Aid B. bowl of salad C. tablespoon of salt D. cup of sugar

The correct answer is A. Kool-Aid is an example of a solution because of the things that are dissolved into the water. For example, to make Kool-Aid you would use a powdered flavoring and sugar. Salad is an example of a mixture. The items put into a salad keep their physical properties and they can be easily separated. Salt and sugar can be used to make a solution but by themselves they are simply a substance.

4. Some students wanted to test the rate at which salt dissolves in water. They put 10g of salt and 200mL of water into each beaker. In which beaker will the salt dissolve the fastest? A.Beaker KC. Beaker M B. Beaker LD. Beaker N

The correct answer is D. Remember that a substance will dissolve faster into a liquid that has been heated to a higher temperature. Beaker N has the greatest temperature at 35 ° Celsius. This means that the salt will dissolve at a faster rate than in the other beakers.

You can make a solution when you stir sugar into water. The sugar dissolves and the water remains clear.

Do all substances dissolve? No…if you mix sand with water, the sand does not dissolve but settles on the bottom of the glass. Sand + water

All solutions are mixtures but not all mixtures are solutions  Sugar + Water = ? Mixture and a solution  Sand + Water = ? Mixture but not a solution

Other examples of solutions:  Soda = Gas + Liquid  Jewelry = Solid + Solid  Air = Gas + Gas

Solutions can be separated  Most solutions can be separated by evaporation.  To separate a saltwater solution, let the water evaporate.  Once the water is gone, the salt will be left.

Challenge  You are given a mixture of salt, sand, and gravel. Design a plan to separate this mixture? What tools would you use? List your steps in order.