A CLOSER LOOK AT MATTER

Atoms, elements, compounds and mixtures

What’s the Matter?

Defining Matter

• define matter

• classify an item as matter or not matter

You will be able to:

• Items that are clearly matter are all objects, or

things, that are tangible.

• Energy and ideas are not matter, but they

involve matter.

• Matter has some sort of dimension and

substance to it.

A good definition should work 100% of the time.

Here are some textbook definitions of matter:

• Matter: Anything that has substance and takes up

space.

• Matter: Anything that has mass and volume.

windcloudsmusic

Everything that has mass and takes up space

is matter, yet some things do not consist of

matter.

Here is a list of 10 examples of non-matter.

Basically, any type of energy or any abstract

concept is an example of something that is not

matter.

time sound

light color

love thoughts

gravity microwaves

heat memories

information reflections

Why aren’t light and heat

matter?

The universe consists of matter and energy. The

Conservation Laws state that the total amount of matter

and energy are constant in a reaction, but matter and

energy may change forms.

Energy describes the ability to cause change. While

matter may have energy, they are different from each

other.

One easy way to tell matter and energy apart is to ask

yourself whether what you observe has mass. If it

doesn't, it's energy!

Examples of energy include any part of the

electromagnetic spectrum, which includes visible light,

infrared, ultraviolet, x-ray, microwaves, radio, and gamma

rays.

Other forms of energy are heat (which may be considered

infrared radiation), sound, potential energy, and kinetic

energy.

Another way to distinguish between matter and energy

is to ask whether something takes up space. Matter

takes up space. You can put it in a container. While

gases, liquids, and solids take up space, light and heat

do not.

Usually matter and energy are found together, so it can

be tricky to distinguish between them. For example, a

flame consists of matter in the form of ionized gases and

particulates and energy in the form of light and heat.

You can observe light and heat, but you can't weigh

them on any scale.

summary

• Chemists study all kinds of matter.

• Matter is everything that has substance and

takes up space, or that has mass and

volume.

Your brain is an example

of matter, ideas are not.

What is matter?

• Matter is anything that has mass and

takes up space.

• Matter can be classified by extensive or

intensive properties.

• Extensive depends on the amount of

matter in the sample.

• Intensive does not depend on the amount

but the type of matter in the sample.

Matter is made up of…

compounds

elements combine to form larger

particles called compounds.

Classification model

Separating mixturesChromatography of inks

PHYSICAL AND CHEMICAL

PROPERTIES OF MATTER

What stuff is made of and how it reacts

• Property: A characteristic of a

substance.

• Matter has observable and measurable qualities.

• We can use general properties to identify substances.

All substances have properties…

Example:

People can be identified by their …

Face (shape,

expressions) Voice HeightFinger prints

Eye color Hair color Teeth DNA

Physical Properties: Characteristic of a

substance that can be observed without

changing the substance into something else.for example: mass, color, hardness, size, texture, odor

Chemical Properties: characteristics involved

when a substance interacts with another

substance to change its chemical make-up.for example: pH, flammability, rusting (oxidizing), gassing

Properties are used to identify, describe

and classify matter.

examples of physical properties

commonly used in chemistry:

• state, freezing point, boiling point, melting point, viscosity, density, luster and many more.

–viscosity - The resistance of a liquid to flowing.

Low viscosity-water, rubbing alcohol

High viscosity-honey

Physical properties of matter are categorized

as either: Intensive or Extensive:

•Intensive - Properties that do not depend on the amount of the matter present.

– color, odor, luster

– malleability, ductility, conductivity

– Density

Extensive – Properties that change when the size of the sample changes.

• mass, volume, length

• total charge

Chemical properties

• A common chemical property is reactivity.

– Reactive to oxygen

– Reactive to air

– Reactive to water…

Note that chemical properties

aren’t EASY to observe,

unlike physical properties.

examples of chemical properties

commonly used in chemistry:

• Flammability, corrosivity, oxidation state, and more

oxidation - The loss of electrons.

When a substance is oxidized, it’s properties change

for example –

silver tarnishes

metals rust

Did you know?

Fruit exposed to the air is oxidized (the oxygen steals

electrons from the compounds in the fruit’s cells) and

turns brown.

The process is very similar to the

rusting process of metals. The

oxidized form of these compounds

is different from the unoxidized form

and is, unfortunately, unappealing

to eat.

antioxidantsMany 'superfoods' are advertised as containing

antioxidants. An antioxidant is a compound that

reduces the oxidation of other compounds.

In theory, consuming antioxidants will help our bodies

fight off the harmful effects of oxidation, keeping our

cells and enzymes happy and healthy. In other words,

eating things like blueberries and chocolate will

help our insides from looking like

browning fruit.

PHYSICAL AND CHEMICAL

CHANGES

How do you Know?

Remember: You can change substances physically and

chemically.Physical Changes -- Do Not form new substances.

Chemical Changes -- Do form new substances.

Physical change : a change that affects one

or more physical property

Test for a physical change - can it be

undone?

Because physical changes do not fundamentally alter the

identity of the substance, they are often easy to undo.

Some examples of physical

changes:

chemical change: a change that alters the

substance and changes it into something new

How do you know if it is a

chemical or physical property?

If it can Change and can’t be reversed, it’s

CHemical

Test for a chemical change – can it

be undone?

Are the properties of the

new substance different

than the original properties?

How can you tell if a physical or

chemical change has taken place?

• A precipitate is formed • density changes

• Heat is released • a color change

• Gas is produced • light or sound is produced

• pH changes • A new odor is formed

Is it a physical or chemical change?

Breaking glass

Frying an egg

Shaking pop

Ice pack

Burning a match

Freezing

water

Hand warmers

Cooking

macaroni

Rusting car

Boiling water

Chopping

veggies

Baking a cake

SORT IT OUT

Is a physical or chemical

change occurring?

Chemical Reactions

• remember - Clues that a chemical change has occurred are: – energy transfer (heat increase or decrease), change in

color,

– gas production,

– formation of a precipitate (solid formed)

Cool chemical

reactions

Chemical Reactions

• During a chemical change, the composition of matter always changes.

– A substances present at the start of the reaction are called the reactants.

– The substances present at the end of the reaction are called the products.

reactants product

Chemical Reactions

• During a chemical change, the composition of matter always changes.

– During any chemical reaction, the mass of the reactants and the products must equaleach other.

• This is the Law of Conservation of Mass.

During ordinary physical or chemical

processes matter can neither be created

nor destroyed. It can only change forms.

Law of Conservation of Mass

indicators

• Indicators are used extensively in lab testing.

• Indicators are usually organic dyes.

• Indicators change color

based on the pH of the

substance – so you

know whether

something is acidic or

basic.

• They do not cause and

are not part of the

reaction

Commonly used indicators - examples:

Test for acid

Phenolphthalein pH Tester

Test for basepH = 7.6

Let’s Do

CHEMISTRY

HOW DO YOU KNOW YOU

MADE SOMETHING NEW?

Lab:

How do You Know You Made

Something New?

HCl + NaHCO3 → ???

Hydrochloric acid + sodium bicarbonate look like

they are reacting chemically. Why?

reactants products

• Was the gas one of

the products?

• Can you demonstrate

conservation of

mass?

• What do you think the

product is?

How do You Know You Made

Something New?

HCl + NaHCO3 → ??

Hydrochloric acid + sodium bicarbonate yields

carbon dioxide, water and salt.