Properties of Matter

Physical Properties How would you describe an orange to someone who has never seen one? How would you describe an orange to someone who has never seen one? Orange in color Orange in color Round Round Waxy feel to the rind Waxy feel to the rind Juicy Juicy Sweet Sweet Each of these is a physical property Each of these is a physical property Anything that can be observed or measured without changing the matter’s identity Anything that can be observed or measured without changing the matter’s identity Without changing what the matter is Without changing what the matter is

Examples of physical properties Color Color Shape Shape Odor Odor Mass Mass Volume Volume Magnetism Conducting electricity strength flexability

Physical properties cont’d Using physical properties every day: Using physical properties every day: The “smell” test for dirty clothes The “smell” test for dirty clothes Color of fruit to see if its gone bad Color of fruit to see if its gone bad Odor of milk to see if it has spoiled Odor of milk to see if it has spoiled

Density Density is the amount of matter in a given space (volume) Density is the amount of matter in a given space (volume) In a density column, like the one at right, layers are formed based on the density of each liquid In a density column, like the one at right, layers are formed based on the density of each liquid The more dense something is, the more mass there is in it The more dense something is, the more mass there is in it All of these liquids have the same volume but not the same mass All of these liquids have the same volume but not the same mass The heaviest liquids will sink to the bottom because they are the most dense The heaviest liquids will sink to the bottom because they are the most dense

Density Density is found by dividing the mass of an object by its volume Density is found by dividing the mass of an object by its volume D = m/v The unit for density is a unit of mass divided by a unit of volume The unit for density is a unit of mass divided by a unit of volume Ex: g/cm 3 or g/mL or kg/m 3 Ex: g/cm 3 or g/mL or kg/m 3

Density practice What is the density of an object with a mass of 120 g and a volume of 7 mL? What is the density of an object with a mass of 120 g and a volume of 7 mL? We have an object with a density of 620 g/cm 3 and a volume of 75 cm 3. What is the mass of the object? We have an object with a density of 620 g/cm 3 and a volume of 75 cm 3. What is the mass of the object?

Density practice Now let’s practice

The states of matter The states of matter are the physical forms in which a substance can exist The states of matter are the physical forms in which a substance can exist Solid (IE: Ice) Solid (IE: Ice) Liquid (IE: drinking water) Liquid (IE: drinking water) Gas (IE: steam) Gas (IE: steam)

The difference in the states All matter is made up of tiny particles called atoms and molecules All matter is made up of tiny particles called atoms and molecules These atoms and molecules are constantly in motion and bumping into one another These atoms and molecules are constantly in motion and bumping into one another The way these particles interact determines what state a substance is in The way these particles interact determines what state a substance is in

The different states cont’d Solids: the state of matter that has a definite shape and volume Solids: the state of matter that has a definite shape and volume IE: wood, ice, a metal pipe IE: wood, ice, a metal pipe In a solid, the particles are very close together In a solid, the particles are very close together The particles only vibrate in place, they do not move from their immediate location The particles only vibrate in place, they do not move from their immediate location KE is low KE is low

The different states cont’d Liquids: the state of matter that has a definite volume, but not a definite shape Liquids: the state of matter that has a definite volume, but not a definite shape IE: tap water, soup broth, rubbing alcohol IE: tap water, soup broth, rubbing alcohol The particles of a liquid can move past each other so that the liquid takes the shape of the container The particles of a liquid can move past each other so that the liquid takes the shape of the container The particles do not move freely from one another The particles do not move freely from one another Some KE Some KE

Gas: the state of matter with no definite shape or volume Gas: the state of matter with no definite shape or volume IE: steam, oxygen, helium IE: steam, oxygen, helium The particles move quickly and freely from each other The particles move quickly and freely from each other High KE High KE The different states cont’d

Chemical Properties Describe matter based on its ability to change into new matter that has different properties Describe matter based on its ability to change into new matter that has different properties Ex: flammability is the ability of a substance to burn Ex: flammability is the ability of a substance to burn Wood is flammable – when it burns, it turns to ash Wood is flammable – when it burns, it turns to ash Ex: Reactivity is the ability of two or more substances to combine and form one or more new substances Ex: Reactivity is the ability of two or more substances to combine and form one or more new substances

Examples of chemical properties Flammability Flammability The ability to catch on fire The ability to catch on fire toxicity toxicity The ability to be poisonous The ability to be poisonous oxidation oxidation The ability to react with oxygen The ability to react with oxygen Why apples turn brown and metal rusts Why apples turn brown and metal rusts combustion combustion The ability to explode and burn The ability to explode and burn

What’s the difference between the two types of properties/? Physical properties can be observed (changing the size, color, shape of a substance) Physical properties can be observed (changing the size, color, shape of a substance) You can’t always easily see chemical properties (you can’t know if something is flammable until you try to set it on fire) You can’t always easily see chemical properties (you can’t know if something is flammable until you try to set it on fire)

Physical Changes Physical changes only affect one or more physical properties of matter Physical changes only affect one or more physical properties of matter Even though its melted, this is still a popsicle Even though its melted, this is still a popsicle You can still get the You can still get the original substance back if it has gone through a physical change What are some other What are some other examples of physical changes?

Examples of physical changes Ripped paper Ripped paper smashing up your car Sanding wood Why are these all physical changes?

Chemical changes Happen when one or more substances are changed into new substances that have new and different properties Happen when one or more substances are changed into new substances that have new and different properties Signs of chemical changes: Signs of chemical changes: change in color or odor, change in color or odor, production of heat, production of heat, bubbling, bubbling, sound or light being given off sound or light being given off Once a chemical change has occurred, you can rarely get back the original substances Once a chemical change has occurred, you can rarely get back the original substances Chemical changes change the composition (type) of the matter involved Chemical changes change the composition (type) of the matter involved

What’s the difference between the two types of changes? Most physical changes are easily reversible Most physical changes are easily reversible Because you are changing what the matter looks like, not the actual matter itself Because you are changing what the matter looks like, not the actual matter itself You can not reverse chemical changes You can not reverse chemical changes because you are left with new substances because you are left with new substances You have not only changed what the matter looks like, but the actual matter into something new You have not only changed what the matter looks like, but the actual matter into something new

Which one is it? Are the following physical or chemical changes? Are the following physical or chemical changes? boiling water boiling water tearing clothes tearing clothes tarnishing silver tarnishing silver lighting a match lighting a match chewing a food chewing a food breaking a stick breaking a stick rusting nail rusting nail burning gas in a stove burning gas in a stove melting ice cream melting ice cream sawing wood sawing wood digesting food for energy digesting food for energy stretching a rubber band stretching a rubber band

Review 1. Explain why a golf ball is denser than a ping pong ball even though they are the same size 2. How can you determine that a coin is not pure silver if you know the mass and volume of the coin? 3. The Statue of Liberty was originally a copper color. After being exposed to the air, she turned a greenish color. Did a physical or chemical change take place? How do you know? 4. Describe the difference between physical and chemical changes in terms of what happens to the matter involved in each kind of change