1 Elements, Compounds & Mixtures Section III Chapter 4Elements, Compounds & Mixtures Section III
2 Section 3 - Mixtures III. MIXTURES A. Properties of mixtures – A Mixture is acombination of chemical substances that arenot chemically combined.1. Substances in a mixture retain theiridentity.a. In some mixtures you can see theindividual pieces (pizza).Introductory movie
3 Section 3 - Mixturesb. In other Mixtures you cannot see all of the components (Salt water).Pizza doughlemonade
4 Section 3 - Mixtures 2. Mixtures can be physically separated. a. Picking the pieces of the mixture apart.Either by hand for big particles (pizza) or by a filter for medium sized particles. (Coffee grounds) or distillation (for really small particles)
5 Section 3 - Mixtures c. Magnets- can sort out metals that can be magnetized.d. Density - can be used to separate mixtures.By adding water if one of the items has a density less than water orCentrifuge-can spin items of different in to layers. e. Some mixtures need to be separated usingseveral steps.
6 Section 3 - Mixtures3. The components of a mixture do not have a definite ratio.a. The amount of things in a mixture does not matter.b. The air is made of nitrogen, oxygen and other gases including water. Some days the air has more water than others. Air is a mixture.
7 Section 3 - Mixtures B. Solutions- 1. A solution is a mixture that appears to be asingle substance but is composed of particlesof two or more substances distributed evenlyamongst each other.The pieces of the mixture are VERY small. So small that they cannot be seen, filtered or even reflect light
8 Section 3 – Mixtures a. Because it has the same appearance and properties through out the mixture it isoften described as a homogeneousmixture.b. The process in which the particles separate andspread evenly throughout a mixture is calleddissolving.c. The solute is the substance that is dissolved andthe solvent is the substance the solute isdissolved in.Solutions movie
9 d. A solute is soluble or able to dissolve. If a substance is insoluble it will form a mixture that is not homogeneous and therefore is not a solution.
10 Section 3 - Mixtures e. If two liquids or two gasses combine to form a solution the substance with the greater volumeis the solvent.f. Alloys are solid solutions of metals or nonmetals dissolved in metals. For example brassis an alloy of Zinc dissolved in copper.BrassAlloy Video-UnitedstreamingThis is an alloy of indiumGallium and tin that is aliquid at room temperature
11 Section 3 - Mixtures2. Particles in solutions are extremely small. So small thatthey never settle out, cannot be filtered out and they donot even scatter light.3. Concentration is a measure of how much solute isdissolved in the solvent.Deep concentration!
12 Section 3 - Mixturesb. Solutions can be described as concentrated or dilutebut these are not specific descriptions.c. A solution that contains all the solute it can hold ata given temperature is said to be saturated. Anunsaturated solution contains less than it can hold.
13 SOLUBILITY CHART FROM TEXT Section 3 - Mixtures4. Solubility of a solute is the amount of soluteneeded to make a saturated solution using agiven amount of solvent at a certaintemperature.a. Solubility is expressed in grams of solute per 100mL of solvent.b. There is a solubility chart on p 95.c. The solubility of gasses in liquids decreasesas temperature is raisedSOLUBILITY CHART FROM TEXT
14 Section 3 - Mixtures 5. What effects how fast a solid dissolves? a. Mixing- stirring or shaking helps particles separateand mix with the solvent.b. Heating- causes particles to move more quicklycausing solvent to spread out and mix with solvent.c. Crushing- increases the amount of contact betweenthe solute and the solvent. Allowing the solvent todissolve more quickly.
16 Section 3 - MixturesC. Suspensions- a mixture in which particles are dispersed throughout the liquid or the gas but are large enough that they settle out.Suspension Video-Courtesy Unitedstreaming1. The particles are insoluble so they do not dissolve.2. Suspensions are usually described as heterogeneous mixtures (video). Because the different components are easily seen.
17 Section 3 - Mixtures 3. Characteristics of suspensions: a. Particles are fairly large and they scatter orblock light.b. Particles are too heavy to stay mixed withoutbeing stirred or shaken.c. Passing it through a filter can separate asuspension.
18 Section 3 - MixturesD. Colloids-a mixtures in which the particles are dispersed through out but are not heavy enough to settle out. Colloid Video-Unitedstreaming1. Colloids have properties of both solutions andsuspensions.2. The particles in a colloid are large enough to scattera beam of light.3. The particles in a colloid cannot be filtered out ofthe mixture.
19 Section 3 - MixturesExamples of colloids include- milk, gelatin, whipped cream, deodorant, and mayonnaise.Photos courtesy google.com
20 Build comparison 5 block chart Note to Mrs. Martin remember that they have difficulties comparing the substances re teach how this goes so the tests will be ok