Properties of Matter

What is Matter? A. Matter is anything that has mass and takes up space. B. Matter has different properties or characteristics. { Chemistry is the study of the properties of matter and how matter changes.}

II. Composition of Matter Substance – matter with a fixed composition or make up. It also has definite properties. It is pure. a. Sodium Chloride, NaCl (table salt) is always exactly the same no matter what brand it is or where it comes from. It is a pure substance.

b. Blueberry muffin batter is. made up of different. ingredients b. Blueberry muffin batter is made up of different ingredients. Some of the ingredients are substances. Each recipe is different. Each batch is different no matter how hard you try to make it the same. Blueberry muffin batter is not a substance.

“substances” or “not a substance” Group as “substances” or “not a substance” table salt 2. pizza 3. distilled water 4. silver 5. air 6. mud 7. oxygen 8. Sugar 9. rock 10. tap water

Substance: table salt, sugar, distilled water, silver, oxygen. Not substances: pizza, air, mud, rock, tap water. How did you do? Make a list of your own and exchange with a friend. See if you both can sort things out. Discuss your answers.

All matter has two kinds of properties: Physical: can be observed (using your senses.) Without changing it into another different substance. How hard is it? Is it rough? What color is it? Will it dissolve in water? Is it a solid, a liquid or a gas? Can it bend? The state of matter is a physical property.

These physical properties can be used to classify matter. a. for example, metals have luster (they are shiny) and they conduct electricity. Can you think of other properties metals have in common?

Four States of Matter (review) A. Solid – definite volume and definite shape -particles are tightly packed together - very little motion, vibrate only - strong attraction between particles

B. Liquid - definite volume but no definite. shape B. Liquid - definite volume but no definite shape – particles are tightly packed together – particles have the ability to move (flow) – particle attraction not as strong as that of a solid – viscosity – the resistance of a fluid to flow (strong attraction = high viscosity = slow moving) Ex: gel

D. Gas – no definite volume or shape - particles are far apart - particles move in random motions; very fast - little or no particle attraction - pressure is exerted by the atoms of the gas hitting the sides of the container

E. Plasma – no definite volume or shape - consists of electrically charged particles. - has large amounts of energy - stars!!

States of Matter

2. Chemical property: the property of a pure substance that describes (identifies) its ability to change into a different substance.. If you have a piece of paper and burn it, it is no longer paper. It has let off a gas, the solid has become ash. Heat is released.

Burning, giving off heat, is a chemical property. Chemical properties are also used to classify substances. Some substances change, like iron combines with oxygen to form rust. Some substances like gold do not change or react.

C color change (not just adding a dye, rusting) O odor change (rotting meat) T temperature change (a chemical ice/heat pack) B bubbles ( baking soda mixed with vinegar) P precipitation (clumpy, spoiled milk) These are 5 indicators of a chemical change. Think of a pneumonic to remember these things.

If two or more of these indicators are present then it may be a chemical change! Adding crystal light to water may change the color and it may have a sweet smell but it is not a chemical change. The crystal light is just dissolved in the water, the water is still water. Evaporate the water and crystal light is at the bottom of the glass. H2O has gone into the air. Each thing is still the same substance .

Leaving milk on the counter so it goes bad IS a chemical change. It smells (odor) It becomes chunky (precipitate) The milk may change color also It is no longer milk. Can you come up with another chemical change?

You have a container of water, H2O, at room temperature, it is liquid You have a container of water, H2O, at room temperature, it is liquid. You put it in a freezer, it becomes a solid as the temperature drops. Is this a physical or chemical change? Support or defend your answer.

Steam Water Ice Water is always H2O, it will change state as temperature changes but it is still H2O. Solid, liquid, or gas.

Energy determines the state!

E. Properties of Matter – 4 types 1. Chemical Property – the way a substance reacts with others to form new substances with different properties. a. describe how a substance reacts b. involve the reactivity of elements or compounds c. flammability, combustibility

2. Physical Property- characteristic of a substance that can be observed or measured without changing the composition of the substance. a. can be observed with senses b. shape, color, odor, melting point, freezing point, density c. properties remain constant for pure substances

Chemical Changes Chemical change — change that transforms one substance into another substance Example- Burning hydrogen (H2) in oxygen (O2) gives H2O.

3. Chemical Change – a change that occurs when a substance changes composition by forming one or more new substances Fruits/vegetables ripen or rot Food being digested Rusting metal Rotting wood Two elements combine chemically; silver tarnishing Burning paper

4. Physical Changes – a change in the physical form/properties of a substance that occurs without a change in composition. Changing the state does not change the composition or mass Ex: cutting a piece of paper

Physical vs. Chemical Examples: rusting iron? dissolving in water? burning a log? melting ice? grinding spices? chopping a log in half?

Characteristics of Physical Changes Melting point Boiling point Vapor pressure Color State of matter Density Electrical conductivity Solubility Adsorption to a surface Hardness Physical changes are characterized by the following:

Characteristics of Chemical Changes Reaction with acids Reaction with bases (alkalis) Reaction with oxygen (combustion) Ability to act as oxidizing agent Ability to act as reducing agent Reaction with other elements Decomposition into simpler substances Corrosion Chemical Changes are characterized by the following:

Physical or Chemical? physical Examples: melting point chemical flammable density magnetic tarnishes in air

Phase Changes

Changes between Solids & Liquids Melting: change in state from a solid to a liquid Melting occurs at a specific temperature called, melting point A change from a solid to a liquid involves an increase in thermal energy Cannot be compressed and can only be broken

Changes between Solids & Liquids Freezing is the change of state from liquid to a solid A change from a liquid to a solid is a decrease in thermal energy Cannot be compressed and can only be broken

Changes between Liquid & Gas Vaporization takes place when the particles in a liquid gain enough energy to form a gas. Vaporization that only occurs on the surface is called evaporation Example: Shrinking puddle

Changes between Liquid & Gas The opposite of vaporization is called condensation. Condensation occurs when particles in a gas lose thermal energy to form a liquid

Changes between Liquid & Gas Vaporization takes place when the particles in a liquid gain enough energy to form a gas. Boiling: from a liquid to a gas below its surface and at the surface Boiling point: temperature at which a liquid boils

Changes between Solid & Gas Sublimation, particles of a solid that go directly to a gas

3. How fast a substance can catch on fire or burst into flamEs! Combustibility How fast a substance can catch on fire or burst into flamEs!

Flammability Flammability- The ability of a substance to burn What cannot burn??  

Law of Conservation of Mass Mass cannot be created or destroyed; but matter can change from one form to another Phase changes- a. freezing – liquid to a solid; water to ice b. melting – solid to a liquid; ice to water c. evaporation – liquid to a gas; water to moisture in air d. condensation – gas to a liquid; liquid on side of a glass, dew on plants e. sublimation – solid directly to a gas; dry ice, moth balls, candles