Composition of Matter

PROPERTIES OF MATTER

• What is matter?

• What is mass?

Anything that has mass and takes up space

The amount of matter an object contains

SUBSTANCES

• A substance is matter that has a definite and uniform composition

One type of “stuff”

TYPES OF SUBSTANCES

• There are two different types of substances:

One type of “stuff”

ELEMENTS

• An element is the simplest forms of matter.

• Each element is represented by a chemical symbol.

Carbon is an elementElements are made of atomsDiamonds are made of atoms of the element CarbonFoil is made of the atoms of the element Aluminum.

Atoms are matter

• Carbon is an element• Elements are made of atoms• Diamonds are made of atoms of the element

Carbon• Foil is made of the atoms of the element

Aluminum.

Atoms are matter• Elements most abundant in the earth

and human body are:

Elements

• Pure substance that consists entirely of one type of atom

Hydrogen Sulfur Magnesium

COMPOUNDS

• 2 or more elements combine to make a compound

• A compound is a substance that can be separated into simpler substances only by chemical means

COMPOUNDS

• Examples:

Water - H20

Salt - NaCl

Hydrogen Peroxide - H2O2

Molecules

• Smallest unit of a substance that exhibits all of the properties characteristic of that substance

• They act as a unit–Example: water H2O

Molecules

• Most molecules are made of atoms of different elements, but some can be made of atoms of the same element.

TYPES OF MATTER

chemicallyseparable

MIXTURES

• A mixture is a physical blend of two or more substances that can be physically separated.

• How?

One type of “stuff” More than one type of

“stuff” together

Pure Substance

vs. Mixture

• When people say “Pure Grape Juice” this means it contains only the juice of the grapes with NOTHING added or taken away

• In reality, grape juice is NOT a pure substance. It is a MIXTURE!!!

Mixture

• A combination of more than one substance– Grape juice is a mixture because it contains

water, sugars, acids, and vitamins– The composition of grape juice is not fixed;

it can have different amounts of water, sugars, or other compounds

MIXTURES

Not uniform Uniform throughout

physically

separable

HETEROGENEOUS vs. HOMOGENEOUS

• There are 2 different types of mixtures.–A heterogeneous mixture has more

than one phase or substance (looks different)

–A homogeneous mixture has only one phase (looks the same)• Also called a SOLUTION

Heterogeneous Mixtures

• Mixtures of this type are not the same throughout. – Example: Fruit Salad

• Each spoonful of fruit salad would give you a different variety – no 2 spoonfuls would be exactly the same.

Heterogeneous Mixture

SUSPENSION

a mixture that looks uniform when stirred or shaken that separates into different layers when it is no longer agitated

COLLOID

• Gelatin heterogeneous mix–Gelatin is a colloid–Colloid a mixture of very tiny

particles of pure substances that are dispersed in another substance but do not settle out of the substance

Colloids

• Differences between suspensions and colloids:

• Particles in colloids are much smaller• Because they are so small, they do NOT separate out

or settle to the bottom in colloids• Particles stay dispersed throughout the mixture

• EXAMPLES:• Fog• Milk• Shaving cream• Egg white• Paint• Blood

Colloids

Types of Heterogeneous Mixtures

• Colloids– Particles never settle– Displays the Tyndall Effect

• Scattering of light particles• Ex) Fog, milk, shaving cream

Homogeneous Mixtures

• These mixtures are uniform, in that no matter where you get your sample from in the mixture – each sample will be the exact same. – Examples: Kool-Aid, tomato soup, salt

water, brass keys

Homogeneous Mixtures

• Not only look uniform, they ARE uniform

• Ex: Salt water• If you add salt to a glass of pure water and mix

it, it will eventually look like pure water• Looks uniform because the components of the

mixture are too small to be seen

Homogeneous Mixtures

• When salt and water mix, no chemical reaction takes place

• Easy to separate the 2 substances by evaporating or boiling the water

• Once boiled, only left with salt

homogeneous heterogeneous

Solutions and Homogeneous mixtures

SOLUTIONS & HOMOGENEOUS MIXTURES are synonymous.

Homogenous mixtures are mixed completely, all the way down to their most fundamental particles-atoms, molecules, or ions.

Types of Heterogeneous Mixtures

• Colloids– Particles never settle– Displays the Tyndall Effect

• Scattering of light particles• Ex) Fog, milk, shaving cream

• Suspensions– Visible particles settle– Require agitation to stay mixed

• Ex) OJ, Italian dressing, sand & water

HETEROGENEOUS OR HOMOGENEOUS?

• Saltwater

• Spaghetti sauce

• Muddy water

• Cough syrup

• Salad

• Brass

Homogeneous

Homogeneous

Homogeneous

Heterogeneous

Heterogeneous

Heterogeneous