The Properties of MatterThe Properties of Matter

Looking at Matter at the Looking at Matter at the Molecular LevelMolecular Level

MatterMatter

Everything is made of MATTER!Everything is made of MATTER!Matter is anything that has volume Matter is anything that has volume

and mass.and mass.Volume is the amount of space an Volume is the amount of space an

object takes up, or occupies.object takes up, or occupies.

Measuring the volume of Measuring the volume of liquidsliquids

Liquids have volume. We measure that volume Liquids have volume. We measure that volume with a graduated cylinder.with a graduated cylinder.

Use the markings to determine the sig figs. Use the markings to determine the sig figs. Always measure at the bottom of the meniscus!Always measure at the bottom of the meniscus! A liquid in any container has a meniscus.A liquid in any container has a meniscus. Liters (L) and mL (milliliters) are most often used Liters (L) and mL (milliliters) are most often used

to express the volume of liquids.to express the volume of liquids.

Solid VolumeSolid Volume The volume in a solid is The volume in a solid is

always expressed in cubic always expressed in cubic units.units.

Cubic means having “three Cubic means having “three dimensions.”dimensions.”

Cubic meters(mCubic meters(m33) or cubic ) or cubic centimeters(cmcentimeters(cm33) are most ) are most often used to express the often used to express the volume of a solid.volume of a solid.

The 3 in mThe 3 in m33 signifies that signifies that three quantities were used three quantities were used to get the final result. to get the final result. (That is a derived (That is a derived quantity!)quantity!)

If each side in the cube If each side in the cube below is 2m, what is the below is 2m, what is the volume of the cube?volume of the cube?

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The major differences The major differences betweenbetween

MASSMASS A measure of the A measure of the

amount of matter in amount of matter in object.object.

Always constant, no Always constant, no matter the location.matter the location.

Measured with a Measured with a balance.balance.

Expressed in Expressed in kilograms, grams, and kilograms, grams, and milligrams.milligrams.

WEIGHTWEIGHT A measure of the A measure of the

gravitational force gravitational force on an object.on an object.

Varies depending Varies depending on where the on where the object is in relation object is in relation to the earth. to the earth.

Measured with a Measured with a spring scale.spring scale.

Mass is a measure of InertiaMass is a measure of Inertia What in the world is inertia?What in the world is inertia? Ever try to move a car? Yeah, it is difficult!Ever try to move a car? Yeah, it is difficult! That is because of inertia!That is because of inertia! Inertia is the tendency of all object to resist a Inertia is the tendency of all object to resist a

change in motion.change in motion. This will cause objects that are still to remain still, This will cause objects that are still to remain still,

and allow objects that are moving to continue and allow objects that are moving to continue moving.moving.

Mass is a measure of inertia because the greater Mass is a measure of inertia because the greater the mass of an object…the more difficult it is to the mass of an object…the more difficult it is to move.move.

Describing MatterDescribing Matter

• Knowing the characteristics or Knowing the characteristics or properties of an object can help you properties of an object can help you identify the object.identify the object.

Properties of MatterProperties of Matter

• There are: There are: • Physical PropertiesPhysical Properties• Chemical PropertiesChemical Properties

Physical PropertiesPhysical Properties

Things that describe the object are Things that describe the object are physical properties.physical properties.

Physical properties can also be observed Physical properties can also be observed or measured without changing the identity or measured without changing the identity of the matter.of the matter.

Examples of physical properties include: Examples of physical properties include: color, odor, size, state, density, solubility, color, odor, size, state, density, solubility, melting point, etc…melting point, etc…

Solids, Liquids, and GasesSolids, Liquids, and Gases

Solid - fixed volume and fixed shapeSolid - fixed volume and fixed shape Liquid - fixed volume and variable shapeLiquid - fixed volume and variable shape Gas - variable volume and variable shapeGas - variable volume and variable shape

Spotlight on DensitySpotlight on Density

Density is a very helpful physical Density is a very helpful physical property.property.

Density = mass per unit of volume or Density = mass per unit of volume or Density = mass/volume Density = mass/volume

Density is an excellent help in Density is an excellent help in identifying substances because each identifying substances because each substance has its own density.substance has its own density.

If Density = mass/volumeIf Density = mass/volume

Then mass = volume x density Then mass = volume x density

oror

m = v x dm = v x d• AND volume = mass/densityAND volume = mass/density

oror

volume =volume = m m

dd

Chemical PropertiesChemical Properties

Chemical properties describe a substance based Chemical properties describe a substance based on its ability to change into a new substance with on its ability to change into a new substance with different properties.different properties.

Ex: wood burns to form ash and smokeEx: wood burns to form ash and smoke Chemical properties cannot be observed with Chemical properties cannot be observed with

your senses.your senses. Chemical properties aren’t as easy to observe as Chemical properties aren’t as easy to observe as

physical properties.physical properties. Examples of chemical properties: flammability Examples of chemical properties: flammability

and reactivity and reactivity

Characteristic PropertiesCharacteristic Properties

The properties that are most useful in The properties that are most useful in identifying a substance are its identifying a substance are its characteristic properties. characteristic properties.

Remember the difference between Remember the difference between physical and chemical properties. physical and chemical properties.

Physical properties can be observed! (with Physical properties can be observed! (with your eyes!) IDENTITY OF SUBSTANCE your eyes!) IDENTITY OF SUBSTANCE DOES NOT CHANGE!DOES NOT CHANGE!

You can observe chemical properties only You can observe chemical properties only in situations in which the identity of the in situations in which the identity of the substance could change.substance could change.

Physical ChangesPhysical Changes

A physical change is a change that affects one or A physical change is a change that affects one or more physical properties of a substance.more physical properties of a substance.

Physical changes do not form new substances! Physical changes do not form new substances! EX: ice melting or sugar dissolvingEX: ice melting or sugar dissolving

Physical changes are easy to undo.Physical changes are easy to undo.

Chemical ChangesChemical Changes

A chemical change occurs when one or more A chemical change occurs when one or more substances are changed into entirely new substances are changed into entirely new substances with different properties.substances with different properties.

You can observe chemical properties only when a You can observe chemical properties only when a chemical change might occur!chemical change might occur!

Examples of chem. changes:Examples of chem. changes:

baking a cakebaking a cake

rustingrusting

Clues to chemical changesClues to chemical changes

Color changeColor changeFizzing or bubbling (gas production)Fizzing or bubbling (gas production)HeatHeatProduction of light, sound, or odor.Production of light, sound, or odor.Formation of a precipitateFormation of a precipitate

Chemical changes are not usually Chemical changes are not usually reversible!reversible!