Chapter 3: Separating Mixtures (pg )

Transcription

1 Chapter 3: Separating Mixtures (pg ) 3.2: Separating Mechanical Mixtures (PB Pg & TB Pg ): Name: Date: Check Your Understanding & Learning (PB pg. 40 & TB pg. 61): 1. What are four methods of separating a mechanical mixture? TB # 1 Four methods of separating a mechanical mixture are: sorting, settling, filtration, and dissolving. 2. Describe one way to separate each of the following mechanical mixtures: TB # 2 a) Metals is a scrap yard: a magnet b) Paper clips and sand: a sieve c) Water and gravel: let the gravel sink to the bottom; then you can pour off the water. d) Salt and sand: They can be separated by mixing the two substances with water. The salt will dissolve into the water, while the sand will settle at the bottom of the mixture. e) Sand and gravel: They can be separated by pouring the mixture into a sieve with holes small enough to trap the gravel but large enough to let the sand through. f) Sand and water: They be separated using a filter the water will pass through the filter but the sand will not. TB # 3. Some air purification systems include filters. How do air filters make the air healthier for people to breathe? The filters allow the clean air to pass through them, but they trap ting solid particles that make the air harmful to breathe. TB # 4. What is the difference between a filter and a sieve? A filter is similar to a sieve in that both are used to separate mixtures by trapping larger substances in holes that allow smaller substances to pass through. However, a filter has much smaller holes than a sieve, so that it is used to separate tiny, insoluble solids from liquids or gases. Sieves can separate larger solids from smaller solids or liquids. 3.4: Protecting The Environment By Separating Mixtures (PB. Pg & TB Pg ): Check Your Learning& Understanding (PB pg. 49 & TB. Pg. 66): 1) What are the two main ways to avoid water pollution? TB # 1 a) to find the pollution source and figure out how to stop it from polluting b) to treat dirty water before it reaches rivers and lakes. 2) How is settling used in sewage treatment? TB # 2 Settling is used during primary and secondary treatment of sewage. Solids and bacteria that are denser than water sink to the bottom of a pool or tank, where they are collected and removed from the water. 3) List 3 sources of water pollution: Oil spills, fertilizers from farms, and salt from roads. 4) Identify 3 methods people use to clean sewage. Sieving, settling,, and filtering. # 4 TB: List only two ways in which pollutants can get into water. a) Pollutants can get into water through exposure to factory waster. Pesticides, salts, and fertilizers from farms and roads also pollute water. b) Pollutants also get into water through accidental spills of leaks. # 5 TB: Why is it particularly difficult to separate oil and water once they are mixed? It is very difficult to separate oil and water once they are mixed because they are both liquids. As a result, many kinds of separation techniques are not very effective.

2 3.5: Separating Solutions (PB Pg & TB Pg ) Name: Date: Overall Expectations: 2 & 3 Specific Expectations: 2.1, 2.3, 2.5, 2.6, 3.4, 3.5, & 3.6 Check Your Learning & Understanding (PB pg. 53 & TB pg. 69): 1. Describe one way to separate sugar from a sugar-and-water mixture. TB # 1 Boil the mixture until the water evaporates, leaving the sugar behind. 2. SKIP 3. What are the two methods of separating solutions. How do they work? 3.7: Mixtures in Industry (PB pg & TB Pg ) Overall Expectations: 1 Specific Expectations: 1.2, 2.5, 2.6, 3.4, & 3.5 Check Your Learning & Understanding (PB pg. 60 & 61 and TB page 76): 1. What kind of mixture is: a) flour? Mechanical Mixture b) Petroleum? Solution c) Uranium ore? Mechanical Mixture 2. Describe one way to separate each of the following mixtures: a) wheat grains with large sticks by sieving wheat grains b) wheat grains with metal pieces by using a magnet to remove the metal 3. Name two products that come from the lighter parts of petroleum. Gasoline, kerosene, and natural gas 4. Describe how uranium is separated from uranium ore. TB # 5 The ore is crushed, and then add water to it to make it a solution. The ore is sieved from the solution, leaving behind uranium particles dissolved in water. The water is allowed to evaporate, leaving behind solid uranium. 5. SKIP TB # 4 a: Why can uranium be used to produce electricity? Because it is a radioactive substance. As the uranium breaks down, it releases energy that can be used to generate electricity. 6. a) Why can waste uranium not be treated the same as regular garbage? Uranium ore cannot be treated the same way as regular garbage because it is highly radioactive, and it would contaminate soil and water if it were buried in a landfill. b) Describe one way in which uranium is disposed of. Uranium ore is sometimes disposed of by mixing it with melted glass, and burying the mixture deep within an unused mine. 7. List two risks and two benefits of nuclear power. Risks: 1) an accident could result in leaked radiation that could cause deadly diseases such as cancer. 2) Nuclear waste is very harmful to the environment. Benefits: 1) It does not produce pollution leading to acid rain, and 2) it does not release carbon dioxide, which contributes to the problem of climate change. 3)

3 Chapter 3 Review (Pages 80 81) 1. Describe one method used to separate the following mixtures into the products indicated: a) sewage cleaner water Use floating and settling to remove solids, grease, and oil. b) wheat grains white flour use a series of sieves c) petroleum (crude oil) gasoline Use a fractional distillation column 2. a) Name a way to separate a solution that contains two liquids Distillation b) Name a way to reclaim solid solute from a solution Evaporate the liquid, leaving the solid behind. 4. How does a filter work to separate the components of a mechanical mixture? A filter separates the components of a mechanical mixture by allowing any liquids and gases to pass through tiny holes n the filter. Solid materials cannot pass through the filter and are trapped. 5. Could you use a magnet to separate any kind of mixture? Why or why not? A Magnet cannot be used to separate any kind of mixture. It can be used only if one of the components of the mixture is attracted to magnets, but the other component is not. 7. Why is it important to remove harmful materials from waste before putting the waste in the environment? It is important to remove harmful materials from waste before putting waste into the environment because those harmful materials could damage the environment and poison plants and animals, including people. 10. a) Wheat grains might arrive at a flour mill mixed up with stones, sticks, etc. What kind of mixture is this? Mechanical Mixture b) When the wheat grains have been crushed, what kind of mixture is this? Mechanical Mixture c) When petroleum arrives at an oil refinery. What kind of mixture is this? Solution 11. Joshua mixed sand with water. Describe two ways to separate Joshua s mixture. a) Settling method. The sand would sink to the bottom of the mixture, and the water could be poured off, leaving the sand behind. b) Use a filter. The filter would allow the water to pass through, but would trap the sand. 13. Chang poured salt into his glass of juice by accident. Can Chang remove all the salt by pouring this juice through a filter? Explain why or why not. No, Chang won t be able to remove all the salt from his juice by using a filter. When salt dissolves in water, it breaks into particles too tiny to see. When Chang pours his drink through a filter, the tiny particles of salt will pass through along with the juice. The filter might trap some undissolved salt if the juice-and-salt mixture is saturated (and can t dissolve any more salt), but it won t trap all of the salt.

4 Unit A Pure Substances & Mixtures - Unit Review (Pages 84 87) Name: Date: 1. Write a definition of matter. Matter is anything that has mass and takes up space. 2. What is matter made of? Matter is made of tiny particles. 3. Write the five main ideas of the particle theory. a) all matter consists of tiny particles b) there are empty spaces between particles c) particles move continuously in random directions d) heating particles increases their speed and the distances between them e) Since particles attract each other, they tend to stay together. 4. What is the difference between the particles of a solid and the particles of a liquid? Solid: Particles: closer together, vibrate, very strong force of attraction (packed closer together) Liquid: Particles: far apart, move faster, force of attraction weaker than in a solid. 5. a) What are the three states of matter b) Use the particle theory to describe each of the three states of matter. See Chapter 1 - Review (pages 32 33), Question # 3 6. a) What is the difference between a pure substance and a mixture? B) Give one example of each. Pure Substance Mixture It is made up on only one kind of particles. It contains more than one type of particle. Example: Oxygen Example: Air 7. a) Name the two types of mixtures and explain how they are different. b) Give one example of each. 1) Mechanical Mixtures 2) Solutions How are they different? You can see and feel the different kinds of matter that make up a mechanical mixture. You cannot see and feel the different kinds of matter that make up a solution. Example: milk and cereal Example: salt water 8. Can you tell if a sample of matter is a pure substance or a solution by looking at it? Explain why or why not. No. In a solution, the different particles combine so thoroughly that it appears to contain only one kind of particle throughout, just like a pure substance. 9. Name two industries that separate mixtures. a) The recycling industry b) The petroleum industry 10. Can you tell if a mixture is a mechanical mixture by looking at it? Explain. Yes, because you can see the different kinds of matter that make up the mixture. 11. Identify each of the following kinds of matter as a pure substance, a mechanical mixture, or a solution: a) Salt Pure Substance b) clear shampoo solution c) table sugar Pure Substance d) a salad Mechanical Mixture e) 14-karat gold solution f) soil Mechanical Mixture 12. Distinguish between a homogeneous mixture and a heterogeneous mixture. A homogeneous mixture is uniform, but a heterogeneous mixture is not. 13. Is air a solution or a pure substance? Explain your answer. Air is a solution. It is made up of a mixture of different kinds of gases. 14. What is the difference between a solute and a solvent? b) Give one example of each. Solute Solvent A solute is the substance that dissolves A solvent is the substance that does the dissolving. Example: Salt Example: Water 15. Draw a model that shows the particles of a gas. Explain your model. See figure 4 on page 15.

5 16. Is a piece of paper a solid, a liquid, or a gas? Explain your answer. A piece of paper is a solid because it has a definite shape and a definite volume. 17. List three different ways pollutants get into the water system. See 3.4, Question # 4 on page David says, Solutions can be solids, liquids, or gasses. Do you agree with him? Explain. Yes, I agree. A solution is a mixture where one substance dissolves in another. The substances can be solids, liquids, or gases. 25. Describe one way to separate each of the following mixtures into its components. Describe the characteristics that make each separation possible. a) iron filings and sand: Use a magnet to attract the iron fillings. The sand will not. b) sugar and water: Evaporate all the water, leaving behind the sugar crystals. c) tea leaves and water: Filter. The tea leaves cannot move through the tiny holes in the filter. 27. Use the particle theory to explain each of the following observations: a) Sugar dissolves in water even if you do not stir or heat the mixture. The attraction between the particles and the sugar is strong enough to separate the sugar crystals into particles. The smaller water particles surround each sugar particle moving into the empty spaces between the sugar particles. By stirring the mixture, you add energy to the particles, making the sugar dissolve faster in the water. b) Stirring or heating makes sugar dissolve in water faster. Stirring or heating water gives the water particles more energy. The particles move faster and bump into the sugar particles with more force, making the sugar dissolve faster. c) You add a drop of red food colouring to a glass of water. You do not stir the mixture, but the food colouring spreads throughout the water. Particles in a liquid have enough energy to be in constant motion. When food colouring is added to the water, the colouring particles and the water particles move around and bump into each other, which spreads the colouring throughout the water. 37. a) Kemisha s glass of ice water has a mass of 35 g. Will the mass change as the ice melts? Explain. No, because when a substance changes state, the number of particles does not change, so the ice will have the same mass before and after it melts. b) Kemisha left her glass of water outside in the sun for the whole day. Will the mass of the water in the glass change? Explain. Yes, because as the water in the glass is heated by the sun, some water particles will evaporate. Those will leave the liquid water and mix with the gas particles in the air. In this way, the water in the glass will lose water particles and mass. 41. Alex dissolves 3 g of sugar in water to make 10 ml of solution. What is the concentration of Alex s solution in grams per 100 ml? The concentration is 30g/100 ml 42. Ling left a glass with some water in it on a counter overnight. The next day, the glass was empty. a) What happened to the water? The water evaporates b) Ling noticed a tiny bit of white solid left in the bottom of the glass. Where might the white solid have come from? The white solid might have come from minerals or other solids, such as calcium, that were dissolved in the water. c) What could Ling have done to prevent the glass of water from emptying? Ling could have covered the glass with a piece of plastic wrap. 43. At 20 o C, you can dissolve no more than 36 g of salt in 100 ml of water. a) How many grams of salt can you dissolve in 50 ml of water? You can dissolve 18 g of salt in 50 ml of water. b) If you dissolve 20 g of salt in 100 ml of water, is the solution saturated or unsaturated? Explain. The solution is unsaturated because 100 ml of water will dissolve 36 g of salt. You have only dissolved 20 g of slat. That means the solution still has room for more solute to dissolve. c) If you dissolve 1 g of salt in 100 ml of water at 20 o C, is the solution concentrated or dilute? Explain why. The solution is dilute because it contains only I g of salt, which makes a small number of solute particles in 100 ml of water.