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Mixtures & Solutions Separation of Mixtures Physical & Chemical Change Acids & Bases

Row 1, Col 1 What is the difference between a mixture and a solution? In a mixture at least two different substances can be seen. In a solution only one type of substance is visible.

1,2 What process does this diagram represent? Filtration

1,3 Is melting an example of physical or chemical change? (Explain why for a bonus 50 points.) Physical Change. (For 2 reasons: 1. Melting can be reversed by freezing. 2. Melting does not create a new substance.

1,4 Give 2 examples of acids and 2 examples of Bases. (25 points each.) Acids: vinegar, lemon juice, pop, battery acid, etc. Bases: blood, Drano, soap, bleach, baking soda, etc.

2,1 Give an example of a solution or mixture that does not contain water. Air & smog, steel (tin & iron), salt & sand

2,2 Which separation strategy was best for separating solutions in water? Distillation. (The other methods only work for separating mixtures, not solutions.)

2,3 Give 4 examples of chemical change. (50 points each) Breathing, combustion (fire), rotting, rust, photosynthesis, chemical reactions, cooking.

2,4 You test a solution with red cabbage indicator and find that it turns purple. Is the solution an acid or a base? Acid. (It has pH 2 which means it is an acid.)

3,1 Which of the following create a solution when combined with water? Sand, salt, sugar, milk, oil, toilet waste. (Bonus 100 – what is the name for both parts in a solution?) Salt and Sugar. (The others do not dissolve.) Bonus – Solvent and Solute.

3,2 What is the name for the process of pouring part of a mixture out of its container? Name 2 advantages and disadvantages of this process. Decantation. Advantages: fast, cheap. Disadvantages: not 100%, can only work on quantities small enough to pour.

3,3 Identify the physical changes from the following list: bending, cutting, melting, smashing, dissolving, grinidng, condensing. They are all physical changes!

3,4 You test solution A to have pH 4 and solution B to have pH 1. How many times more acidic is solution B? (4-1 = 3, 10 3 = 1000)

4,1 A)What needs to be true for filtration to work? B) What needs to be true for sedimentation to work? (200 each) A) The holes in the filter need to be smaller than the particles you are filtering out. B) The particles in the mixture need to have different densities so they will settle out.

4,2 In our separation of mixtures lab, what was the role of the cold water? It helped cool the steam coming from the salt solution and made it condense into water faster.

4,3 Which is more important when determining whether a change is physical or chemical: a) the change cannot be easily reversed or b) a new substance is produced during the change. Explain. b) When a new substance is produced it is always a chemical change. Some physical changes (e.g. ripping something up) can still be hard to reverse.

4,4 What is the name for the reaction when an acid and a base are combined? Is it a physical or chemical change? What is produced during this reaction? (You must answer all 3 questions correctly for the points.) Neutralization reaction. It is a chemical change. It produces salt and water.

5,1 I have 2 beakers with homogenous solutions in them. I shine a light through them as in the diagram. What does it tell me? Explain. (Bonus 50: What is this called?) The one on the left is a mixture because the light hits the particles that are not dissolved. The one on the right is a solution.

5,2 One of the methods of separation we studied in class was called fractured distillation. What characteristic property does this method rely on and what mixture is it commonly used to separate? Boiling point and Oil

5,3 What kind of change (physical or chemical) gives off heat? Which kind of change absorbs heat? Give an example for each. Chemical (both) – burning or breathing and cooking

5,4 You are testing an unknown solution with litmus paper. Red litmus stays red when you put a drop of the solution on it. Blue litmus stays blue. What is the pH of the solution? 7. (If both papers stay the same colour then the solution is neutral and must be pH 7.)