Download Chemistry - The study of matter and the changes it undergoes

Chemistry - The study of matter and the changes it undergoes.
Matter – has mass and occupies space.
Types of matter
 Element – made up of only one kind of atom. (Al)
 Mixture – made up of more than one kind of atom, but no chemical bonds and no
particular ratio. (Saltwater)
o Homogeneous – uniform composition, you don’t have to continue to stir
it. A “solution” of saltwater is a homogeneous mixture. Solutions are
usually clear.
o Heterogeneous – non-uniform composition. You have to continue to stir
the mixture. Chili, chocolate milk, orange juice with pulp, etc.
 Compound – made up of more than one kind of atom, has chemical bonds and
has a specific ratio. (water, sodium chloride)
Substance – Anything that has a definite and unique composition. (elements and
compounds)
Properties of matter
Physical properties – can be observed without changing the substance
 Intrinsic physical properties – remain constant regardless of how much of the
material is present. (Density, specific heat, melting point, etc.)
 Extrinsic physical properties – dependent on the amount of the material present.
(mass, volume)
States of matter
 Solids – contain the least amount of kinetic energy. Particles are held together
and cannot move around, they will vibrate in place. Have a definite shape and
volume.
 Liquids – contain more kinetic energy than solids. Particles are still held together,
but may slide over one another. Have no definite shape, but definite volume
(practically incompressible).
 Gases – contain the greatest amount of kinetic energy. Particles have sufficient
energy to overcome the attractive forces of their neighboring particles. No
definite shape, no definite volume, will assume the volume and shape of their
container.
Changes matter undergo
 Physical changes – result in nothing “new” being produced. May be reversed.
(Freezing, boiling, tearing apart, etc.)
 Chemical changes – result in a new “substance being produced, very difficult, if
not impossible to reverse. (Burning, oxidizing). Evident by an unexpected color
change, heat generated or absorbed, gas given off.