Matter-Properties and Changes

1. Matter-Properties and Changes I will distinguish between physical and chemical properties I will classify matter by composition: element, compound or mixture I will identify observable characteristics of chemical reactions I will explain the fundamental law of conservation of mass

2. Properties of Matter I will identify the characteristics of a substance I will distinguish between physical and chemical properties I will differentiate among the physical states of matter

3. Substances • Matter that has a uniform and unchanging composition • Aka pure substance • Example 1 • Table Salt • Always 100% sodium chloride • Example 2 • Water • H2O • NOT AN EXAMPLE • Sea water • Samples vary by location • Amount of salts, water, dissolved substances

5. Physical Properties • A characteristic that can be observed or measured WITHOUT changing the sample’s composition • Density • Color • Odor • Taste • Hardness • Melting point • Boiling point

6. Examples-Physical Properties • Salt (sodium chloride) • Forms solid white crystals at room temperature • Unique salty taste • Oxygen • Colorless • Gas at 25 degrees Celsius • Melting point -218 degrees Celsius • Boiling point -183 degrees Celsius • Density 0.0014 g/cc

7. Extensive Properties • Dependent upon the amount of substance present • Examples • Mass • Volume • Length • Weight

8. Intensive Properties • Independent of the amount of the substance present • Examples

9. Chemical Properties • The ability of a substance to combine with or change into one or more other substances And/Or • The inability of a substance to change into another substance • Example • Iron forms rust when combined with air • Iron + Nitrogen (at room temperature) = no chemical change

10. Observing Properties of Matter • Every substance has its own unique set of physical and chemical properties • May vary depending on conditions of immediate environment • Room temperature, standard pressure, etc. • Example Copper

12. States of matter • Solid • Liquid • Gas • Plasma • FUN FACT: (only occurs naturally on Earth in the form of lightening bolts!) PHYSICAL PROPERTY!!!!!

13. Solids • A form of matter that has its own definite shape and volume. • Examples • Wood • Iron • Paper • Sugar • Particles are VERY tightly packed • Will only expand SLIGHTLY when heated • Does NOT conform to shape of container • Incompressible • Volume stays the same • Example • Wax (moldable) but volume doesn’t change

14. Liquids • A form of matter that flows, has constant volume, and takes the shape of its container • Examples • Water • Blood • Mercury • Virtually incompressible • Tend to expand when heated • Liquid Particles • NOT rigidly held in place • less closely packed than solids • Are able to move past each other

15. Gases • A form of matter that flows to CONFORM to the shape of its container and fills the ENTIRE volume of its container • Examples • Neon • Lighted signs • Methane • Cooking • Air • Mixture of gases • Particles are VERY far apart • EASILY compressed • A substance NATURALLY in the gaseous state at room temperature RELATED TERMS • Vapor • The gaseous state of a substance that is a SOLID or LIQUID at room temperature • Example • steam

16. Quick Think • Describe the characteristics that identify a sample of matter as being a substance. • Classify each of the following as a physical or chemical property • Iron and oxygen form rust • Iron is more dense than aluminum • Magnesium burns brightly when ignited • Oil and water do not mix • Mercury melts at -39 ℃ • Using what you know about the compressibility of gases, explain why the oxygen in a SCUBA tank is compressed. • Create a table that describes the three common states of matter in terms of their shape, volume, and compressibility.

17. Quick Think- Check • The sample of matter must have a uniform and unchanging composition to be a substance. • Properties • Chemical (rust) • Physical (density) • Chemical (burning) • Physical (mixing) • Physical (melting) point) • Particles of gas are spaced apart and are easily compressed. Therefore, it is possible to put a significant volume of oxygen in the tank, which allows the diver to remain under water longer!

18. Changes in Matter • I will define physical change and list several common physical changes • I will define chemical change and list several indications that a chemical change has taken place • I will apply the law of conservation of mass to chemical reactions

19. Physical CHANGES • Alter a substance WITHOUT changing its composition • Might result in dramatically different appearance (yet leave the composition of the substance unchanged) • Examples • Crunching up a piece of aluminum foil • Cutting a sheet of paper • Breaking a crystal • Phase changes (solid, liquid, gas)

20. Key words of Physical Changes • Bend • Grind • Crumple • Split • Crush

21. Chemical CHANGES • A process that involves one or more substances changing into a NEW substance • New substance • Formed in reaction • Different compositions — than original substance(s) • Different properties — than original substance(s) • Example • Fermentation of juice, sugars, and other ingredients (making wine) • Rusting of iron (a chemical combo of iron and oxygen)

22. Chemical CHANGES • Commonly referred to as a chemical reaction • Reactants • Starting substances • Products • New substances • Example • Reactants = Iron, Oxygen • Product = rust

23. Key Words of Chemical Changes • Explode • Rust • Oxidize • Corrode • Tarnish • Ferment • Burn • Rot

24. The LAW of Conservation of Mass • Mass is neither created nor destroyed during a chemical reaction • Mass is conserved • Mass of Reactants = Mass of Products

25. Conservation of Mass Problem • Known • Mass mercury (II) oxide = 10.0g • Mass liquid mercury = 9.26g • Unknown • Mass formed oxygen = ? g • Mass Reactants = Mass Products • Mercury (II) oxide = Mercury + Oxygen • 10.0g = 9.26g + ? • 0.740 g of Oxygen formed

26. Quick Think • Describe the results of a physical change and 3 examples. Repeat with chemical change. • A friend tells you, “because composition does not change during a physical change, the appearance of a substance does not change.” Is your friend correct? Explain WHY? • Solve each of the following • In the complete reaction of 22.99 g of sodium with 35.35 g chlorine, what is the mass of the sodium chloride formed? • A 12.2 g sample of X reacts with a sample of Y to form 78.9 g XY. What way the mass of Y that reacted?

27. Quick Think-Check • During a physical change a substance is altered but its composition does not change. EX melting, freezing, boiling, bending, tearing • During a chemical change the composition of a substance IS altered. EX color change, odor, temperatures change, formation of gas or solid from a liquid. • The statement is false. Composition doesn’t change but a change in appearance often accompanies a physical change. • 58.44g of sodium chloride • 66.7 g of Y

28. Mixtures of Matter • I will contrast mixtures and substances • I will classify mixtures as homogeneous or heterogeneous • I will list and describe several techniques used to separate mixtures

29. Mixtures • A combination of two or more pure substances • Each pure substance retains its INDIVIDUAL chemical properties • Most everyday matter occurs as mixtures • Substances naturally tend to mix • It is very difficult to keep things pure

30. Mixture Examples • Water and Sand • Water • Colorless liquid • Sand • Grainy solid • Doesn’t dissolve in water • Easily seen as two substances mixed • Water and Table Salt • Water • Colorless liquid • Table Salt • White crystal solid • Dissolves in water • NOT easy to see both substances individually • But if you boiled the water a white residue remains (salt!)

31. Types of Mixtures • Heterogeneous • Doesn’t blend smoothly throughout • Individual substances remain distinct • Examples • Water mixed with sand • Fresh orange juice • Pulp + Juice • Pizza • Dough + sauce + cheese +toppings • Homogeneous • Constant composition throughout • Always has a single phase • Examples • Water mixed with salt • Cough syrup • lemonade • Referred to as SOLUTIONS

32. Solutions • Gas-Gas • EX. Air is primarily a mixture of nitrogen, oxygen, and argon gases • Gas-Liquid • EX. Carbonated beverages contain carbon dioxide gas in solution • Liquid-Gas • Ex. Moist air contains water droplets in air (which is a mixture of gases) • Liquid-Liquid • Ex. Vinegar contains acetic acid in water • Solid-Liquid • Ex. Sweetened powder drink contains sugar and other solid ingredients in water • Solid-Solid • Ex. Steel is an alloy of iron containing carbon

33. Separating Mixtures • Filtration • A technique that uses a porous barrier to separate a solid from a liquid • Ex through filter paper • Like coffee! • Used to filter heterogeneous mixtures composed of solids and liquids • Distillation • A separation technique that is based on differences in boiling points • A mixture is heated until the substance with the lowest boiling point boils to a vapor that can be condensed into a liquid and collected • Used to filter homogeneous mixtures

34. Separating Mixtures • Crystallization • Technique results in the formation of pure particles of a substance • From a solution containing dissolved particles • Ex rock candy • From a sugar solution • Often have to add just a little more than what the solution can possibly hold to get the crystals to come out of solution • Produces HIGHLY PURE solids • Chromatography • Technique that separates the components of a mixture (mobile phase) on the basis of the tendency of each to travel or be drawn across another surface (stationary stage) • EX. Soaking up a liquid with paper towel

35. Quick Think • How do Mixtures and Substances differ? • Classify each of the following as either heterogeneous or homogeneous mixtures • Orange juice • Tap water • Steel (blend of iron/carbon) • Air • Raisin muffin • Applying Concepts • Describe the separation technique that could be used to separate each of the following mixtures • Two colorless liquids • A non dissolving solid mixed with a liquid • Red and blue marbles of the same size and mass