Presentation on theme: "Lesson 4: Mixtures Trail mix is a mixture. A mixture is a combination of two or more substances that do NOT form new substances. There is no chemical."— Presentation transcript:
1 Lesson 4: MixturesTrail mix is a mixture. A mixture is a combination of two or more substances that do NOT form new substances.There is no chemical reaction though. The particles do not bond together.You can separate the trail mix into the original ingredient, and these will be unchanged.
2 Would one substance, like raisins, be considered a mixture? No. A mixture has to have more than one substance.
3 Salt water would be a mixture, because the salt and water do not bond to form one substance. They can be separated.
4 heterogeneous mixture We classify mixtures according to certain properties. There are four types of mixtures.A mixture where the different particles are big enough to see is called a…heterogeneous mixture
5 Trail mix and tossed salads are examples of heterogeneous mixtures Trail mix and tossed salads are examples of heterogeneous mixtures. You can see the separate bits.
6 A mixture where the particles are too small to see is called a… homogeneous mixtureMilk and cream cheese are examples of a homogeneous mixture because you can’t see the individual particles.
7 Some mixtures separate by themselves when their parts settle out into layers. We call this type of mixture a suspension. A suspension is a mixture whose particles settle and separate within a few hours.Oil and vinegar as a salad dressing can be shaken into a smooth-looking mixture. However, the oil lays out on top of the vinegar in a matter of minutes.
8 If the particles in a mixture are the size of atoms or molecules, the mixture is called a solution. A solution can happen when one substance dissolves in another, like sugar and water.All solutions are homogeneous, which means that they have the same makeup throughout.
9 Heterogeneous mixture Discuss the different types of mixtures, and then we’ll fill in the chart.Heterogeneous mixtureHomogeneous mixtureSuspensionSolutionA mixture where you can see the particles of different substancesTrail mixTossed saladA mixture where the individual particles are too small to distinguish and it looks the same throughout.MilkCream cheeseA mixture whose particles settle and separate over time.Oil and vinegarA mixture where the particles are atom-sized and is blended so completely that it looks the same everywhere.Sugar and water
10 What are the parts of a solution? Remember a solution is a mixture where the particles are atom sized, and have the same makeup throughout.There are 2 parts to every solution…
11 solute solvent The part that dissolves is called the The part that does the dissolving is called thesolutesolvent
13 nitrogen In solutions, the solvent is always the greater amount. Air is another example. Air is 78% nitrogen and 21% of oxygen. Which one is the solvent?In the solution of Kool Aid, the water is the solvent—there’s more of it than the Kool Aid powder.nitrogen
14 But there’s a trick with solutions But there’s a trick with solutions. Have you ever tried to wipe up a wet spill with a sponge and the sponge gets too full of liquid to soak up any more?Solutions are similar.
15 After a certain amount of solute is dissolved, no more can dissolve. For example, think about adding sugar to water. If you stir it, the sugar will dissolve. But if you kept adding more and more sugar, soon the sugar would just settle at the bottom. There’s TOO MUCH sugar, and it can no longer dissolve in the water.
16 The greatest amount of solute that is given amount of solvent can dissolve is called the solubility of the solute.The solubility of table salt in water is 37 grams in 100 grams of water at room temperature.If you add more than 37 grams of salt in this amount of water, it will not dissolve.
18 What are the two parts of a solution? Solute = the part that dissolvesSolvent = the part that does the dissolving; the greater partWhat is solubility?The greatest amount of solute that can be dissolved in a certain amount of solvent
19 How can you take mixtures apart? Physical properties are used to separate mixtures. Ways we can separate mixtures are…filtrationflotationsolubilitymagnetism
20 FiltrationOne of the most common methods of separating a liquid and a solid is filtration. Filtration separates substances that have particles of different sizes.A filter is a material with small holes. Small particles pass through the holes, large particles do not. For example: coffee filters, air filters
21 Would you be able to separate a solution using a filter? No, because all of the particles are atom-sized and they’d just pass right through!
22 FlotationIf the 2 substances in a mixture differ in density, it may be possible to use water to separate them by means of flotation.
23 For example, a mixture of sand and cork chips may be separated by pouring in water. The cork chips have a lower density so it floats to the tope, while the heaver sand remains at the bottom.
24 SolubilityLet’s say you have sugar mixed with sand. Pouring water in the container will dissolve the sugar, while the sand will remain solid. Then you can filter the sugar solution into another glass to separate it from the sand. The sugar will then be recovered when the water in the glass evaporates.
25 MagnetismIf you have iron bits mixed with sand, for instance, a magnet can be used to separate the iron pieces from the sand. The magnet will only attract the metal pieces, while the sand remains behind.
26 Let’s watch an animated example of each four methods of separating mixtures.
27 So using these four methods, how would you separate a mixture of sand, sawdust, iron filings, and sugar?1) Add water to dissolve the sugar and float the sawdust. Skim the sawdust off.2) Filter the mixture of sugar, sand, and water, which will take out the sand and the iron filings. Evaporate the water to get the sugar.3) With the sand that is left in the filter, use a magnet to separate the sand and the iron.
28 Remember, the parts of a mixture have different physical properties that can be used to separate them.* density* solubility* magnetism* size
29 How can you separate a mixture How can you separate a mixture? And what is it about mixtures that allows them to be separated?Filtration, Flotation, Solubility, MagnetismThey can be separated using their physical properties.
30 Lesson Review1. What kind of substance is a physical combination of 2 or more substances?A mixture2. A mixture that settles in layers overnight is a…Suspension3. Which passes through filter paper without being separated—a suspension or a solution? Why?A solution passes through filter paper because its particles are the size of molecules and atoms, which is smaller than the filter holes.
31 4. The part of a solution that is dissolved is called the SolventCooloidEmulsionSolutesolute5. If a mixture contains visible particles, it is…a gas.homogeneous.heterogeneous.an element.heterogeneous
32 6. A fruit juice container reads, “Shake well before using 6. A fruit juice container reads, “Shake well before using.” What does this tell you about the juice?It is a suspension.