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April 15General Science Chapter 81 Classification of Matter Chapter 8.

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Presentation on theme: "April 15General Science Chapter 81 Classification of Matter Chapter 8."— Presentation transcript:

1 April 15General Science Chapter 81 Classification of Matter Chapter 8

2 April 15General Science Chapter 82 Matter  Matter: anything that has mass and takes up space.  Atoms: The particles that make up matter.

3 April 15General Science Chapter 83 Classifying Matter Part 1  Substance: Either an element or a compound.  Element: atoms are all alike.  Compound: Made up of two or more elements that are combined.

4 April 15General Science Chapter 84 Compound  Usually have different properties than the elements that make them up.  Compounds always contain the same ratio of the different atoms Example: water (H 2 O) always contains twice as many hydrogen atoms as oxygen atoms

5 April 15General Science Chapter 85 Common compounds  Sugar Contains carbon (black solid), oxygen (colorless gas), and hydrogen (colorless gas)  Table salt NaCl Contains sodium (gray metal) and chlorine (greenish gas)

6 April 15General Science Chapter 86 Classifying Matter Part 2  Mixture: A material made up of two or more substances.  Heterogeneous Mixture: Different materials are spread out unevenly  Homogeneous Mixture: The substances are uniformly spread out.

7 April 15General Science Chapter 87 Mixtures  Don’t always contain the same amounts of different substances. Example: saltwater contains salt and water, but not always in the same ratio Example: permanent press fabric contains a mixture of cotton and polyester, but not always the same percentages.

8 April 15General Science Chapter 88 MATTER Has mass and takes up space SUBSTANCE Composition definite MIXTURE Composition variable ELEMENT One kind of atom COMPOUND Two or more kinds of atoms HOMOGENEOUS Evenly mixed HETEROGENEOUS Unevenly mixed

9 April 15General Science Chapter 89 Discuss #1  What is matter?  What is an atom?  What are the two types of substances?  What are the two types of mixtures?

10 April 15General Science Chapter 810 Discussion #1  What is the difference between a heterogeneous mixture and a homogeneous mixture?  What is the difference between an element and a compound?

11 April 15General Science Chapter 811 Solutions  The particles are spread out so evenly that you cannot see them even with a powerful microscope.  A solution is another name for a homogeneous mixture.  Solutions will never settle.

12 April 15General Science Chapter 812 Solutions  One substance is dissolved in another  Solute – the substance being dissolved  Solvent – the substance that dissolves the solute  When either substance could dissolve the other, the one that there is more of is the solvent

13 April 15General Science Chapter 813 Colloid  A heterogeneous mixture that never settles.  The particles are large enough to scatter light.  A colloid might look cloudy, or it might not, but when you shine a light on it, the light is scattered. Tyndall Effect: The scattering of light

14 April 15General Science Chapter 814 Colloids  Examples Milk – mixture of water, protein, and fat, and other substances. Mayonnaise – mixture of vinegar, sugar, mustard, garlic, eggs, oil, and salt Jello

15 April 15General Science Chapter 815 Suspensions  Heterogeneous mixtures which contain liquid and visible particles that settle.  Examples: Muddy water Orange juice Liquid medications paint

16 April 15General Science Chapter 816 MATTER Has mass and takes up space SUBSTANCE Composition definite MIXTURE Composition variable ELEMENT One kind of atom COMPOUND Two or more kinds of atoms HOMOGENEOUS Evenly mixed HETEROGENEOUS Unevenly mixed SUSPENSIONCOLLOID SOLUTION COLLOID Never settles SUSPENSION Particles settle

17 April 15General Science Chapter 817 Solutions continued  There are many types of solutions and for each there is one solute and one solvent.  When identifying solutions by solute and solvent the solute is usually listed first. Carbon dioxide in pop.  The resulting solution will always be in the same phase as the solvent.

18 April 15General Science Chapter 818 Types of Solutions Liquid – like sugar water  solid and liquid  liquid and liquid  gas and liquid Gaseous – like air  Gas and gas Solid – alloys  Solid and solid

19 April 15General Science Chapter 819 Dissolving solids in liquids  Stirring speeds up dissolving because it brings more solvent molecules into contact with the solute molecules.  Powders dissolve faster than large crystals because they have more total surface area.  Warm solvents dissolve faster than cool ones because their particles are moving faster.

20 April 15General Science Chapter 820 Dissolving gases in liquids  Stirring and heating cause the gas to separate out from the liquid because it can reach the surface and escape faster.  To make the gas dissolve faster you need to cool the liquid and increase the gas pressure.  All gases are more soluble in cooler solvents.

21 April 15General Science Chapter 821 Effects of adding a solute  Lowers the freezing point The solute gets in the way so it is harder for the solvent to form crystals and become solid Antifreeze  Raises the boiling point Solute particles interfere with evaporation so more energy is needed to boil Antifreeze

22 April 15General Science Chapter 822 Discuss #2  What are the 2 parts of a solution? Explain each part.  What is the difference between a colloid and a suspension?  Why do the words “Shake well before using” on a bottle of fruit juice indicate that the juice is a suspension?

23 April 15General Science Chapter 823 Discussion #2  List five different types of solutions with an example of each.  To prevent a carbonated beverage from losing its CO 2 gas, should you open it when it is warm or when it is cool?  How does adding a solute affect the boiling point of a substance? How about the freezing point?

24 April 15General Science Chapter 824 Solution Concentration  Concentrated solutions– contain a lot of solute  Dilute solutions – contain little solute  Not precise terms – qualitative, not quantitative  Solubility: The maximum number of grams of the substance that will dissolve in 100g of solvent at a certain temperature.

25 April 15General Science Chapter 825 Concentration  Can be expressed as a percentage By volume – mL of solute / mL of solution  Usually for liquids in liquids By mass – g of solute / g of solution  Usually for solids in solids By mass and volume – g of solute / mL of solution  Usually for solids in liquids

26 April 15General Science Chapter 826 Solution types  Saturated solution: Has dissolved all the solute it can at a given temperature. Heating the solvent allows it to hold more solute  Unsaturated solution: Any solution that can dissolve more solute at a given temperature.  Oversaturated solution: A solution that has more solute than it can dissolve and the extra solute settles out.

27 April 15General Science Chapter 827 Solution types  Supersaturated solution: Contains more solute than a saturated solution at a given temperature.  Formed by making a saturated solution, then cooling it.  Not stable – adding even one crystal of solute will make the extra solute crystallize.

28 April 15General Science Chapter 828 Discuss #3  What is solubility?  When there is a large amount of solute, the solution is ____________.  The concentration of a solution of a solid in a liquid is usually expressed as a percentage by ___________.

29 April 15General Science Chapter 829 Discussion #3  What is a saturated solution?  What is an unsaturated solution?  What is an oversaturated solution?  What is a supersaturated solution?  What is the difference between a supersaturated solution and an oversaturated solution?

30 April 15General Science Chapter 830 Physical Properties  Characteristics of a material that you can observe easily without changing the substances that make up a material Color Shape Size Density Melting point Boiling point

31 April 15General Science Chapter 831 Physical properties  Some are specific to a particular object An iron nail is pointy, but an iron ball is not. Some copper wires are longer than others. Different sized zinc blocks have different masses.  Some describe a material or substance All iron is magnetic All sulfur is yellow All lead has the same density

32 April 15General Science Chapter 832 Using physical properties  Physical properties can be used to separate mixtures, but not compounds.

33 April 15General Science Chapter 833 Physical Changes  During a physical change, the identity of the element or compound does not change.  Changes in size, shape, or state of matter are all physical changes.

34 April 15General Science Chapter 834 Chemical changes  Change of one substance in a material to a different substance Burning Rusting  Clues that a chemical change has occurred are Odor Foam Sound Color change

35 April 15General Science Chapter 835 Chemical Properties  A characteristic of a substance that indicates if it can undergo a certain chemical change. Flammability Changes in the presence of light Reacts with water Reacts with oxygen

36 April 15General Science Chapter 836 Conservation of Mass  There is no loss or gain of mass during a chemical change.  Mass is neither created nor destroyed during a chemical change.  Example: burning

37 April 15General Science Chapter 837 Discuss #4  Which kind of property can be determined without changing the identity of a material?  A change in size, color, shape, or state of matter is called a ____________ change.  A change of one substance into a different substance is a _____________ change.

38 April 15General Science Chapter 838 Discussion #4  Give two examples of chemical changes. Try to include one that isn’t in your notes.  Give two examples of physical changes. Try to include one that isn’t in your notes.  State the law of conservation of mass.

39 April 15General Science Chapter 839 Vocabulary  Desalination: Removing the dissolved salts from ocean water.  Distillation: Water is evaporated from a salt water solution, leaving the salt behind. The water vapor is cooled (condensation) and the fresh water is collected

40 April 15General Science Chapter 840 Vocabulary  Ionization: When a polar molecule “dissolves” to make ions.  Dissociation: When an ionic compound (usually solids) dissolves in water.  Electrolyte: Solution that conducts electricity when a solute is dissolved in water.  Nonelectrolyte: Solution that does not conduct electricity.

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