CHAPTER 2THE PROPERTIES

OF MATTER

Matter

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

mass. Volume is the amount of space an object

takes up, or occupies.

Measuring the volume of liquids

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

Notice the meniscus in the graduated cylinder. Always measure at the bottom of the meniscus! A liquid in any container has a meniscus. Liters (L) and mL (milliliters) are most often used

to express the volume of liquids.

Solid Volume The volume in a solid is

always expressed in cubic units.

Cubic means having “three dimensions.”

Cubic meters(m3) or cubic centimeters(cm3) are most often used to express the volume of a solid.

The 3 in m3 signifies that three quantities were used to get the final result. (That is a derived quantity!)

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

__________

The Volume of Solids, Liquids, and Gases 1 mL = 1 cm3 REMEMBER THAT! That is why you can compare the volume in

liquids to solids. How do you measure the volume of a gas? You can’t see, so how do you measure it?

ex: balloon

_________________________

Matter and Mass What is mass? Mass is the amount of

matter that something is made of.

Even atoms have mass! Looking at the picture… The mass stays constant in

certain forms of matter such as…__________________.

The mass changes in certain forms of matter such as…_________________.

What is the difference between mass and weight? This is an important concept to understand! Let’s start by understanding gravity. Gravity is the force of attraction between

objects that is due to their masses. All matter experiences gravity! The amount of attraction between two

objects depends on their weight. There is attraction between all objects with

mass, but since they are so small in reference to the earth, the attraction between them is also small.

So, what about weight? Weight is the measure of the gravitational force

exerted on an object! Look at Spot and the rock…which one is attracted

to the earth more through gravitational force? ________________

Which one weighs more? ___________ So, this means the greater the gravitational force,

the greater the weight. Which weighs

more? ------->

Measuring Weight and Mass The SI unit for mass is kilogram (kg). Sometimes we will use milligrams or

grams. (mg or g) The SI unit for weight (or gravitational

force) is NEWTONS. A Newton is approximately equal to the

weight of a 100 gram mass on earth.

The major differences between

MASS A measure of the

amount of matter in object.

Always constant, no matter the location.

Measured with a balance.

Expressed in kilograms, grams, and milligrams.

WEIGHT A measure of the

gravitational force on an object.

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

Measured with a spring scale.

Expressed in Newtons.

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

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

and allow objects that are moving to continue moving.

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

Describing Matter

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

• There are: • Physical Properties• Chemical Properties

Physical Properties Things that describe the object are physical

properties. Physical properties can also be observed

or measured without changing the identity of the matter.

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

Spotlight on Density

Density is a very helpful physical property.

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

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

If Density = mass/volume Then mass = volume x density

or

m = v x d• AND volume = mass/density

or

volume = m

V

Chemical Properties Chemical properties describe a substance based

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

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

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

physical properties. Examples of chemical properties: flammability and

reactivity

Characteristic Properties The properties that are most useful in

identifying a substance are its characteristic properties.

Remember the difference between physical and chemical properties.

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

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

Physical Changes A physical change is a change that affects one or

more physical properties of a substance. Physical changes do not form new substances!

EX: ice melting or sugar dissolving Physical changes are easy to undo.

Chemical Changes A chemical change occurs when one or more

substances are changed into entirely new substances with different properties.

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

Examples of chem. changes:

baking a cake

rusting

Clues to chemical changes Color change Fizzing or bubbling (gas production) Heat Production of light, sound, or odor.

Chemical changes are not usually reversible!