2. Everything is divided into two categories:
Energy: the ability to do work
Matter: anything that has mass and takes up space
3. Properties of Matter: characteristics that can be used
to identify particular substances because these
characteristics are always uniform (the same) in a
particular substance. (examples: boiling point,
hardness)
4. Two Kinds of Properties:
•Physical Properties: This is a characteristic of a
pure substance. The characteristic can be seen
without making any changes to the substance.
Examples: Density, hardness, texture, color, phase,
ability to dissolve in water, and conductivity.
5. Two Kinds of Properties:
•Chemical Properties: This is a characteristic of a
pure substance. The characteristic can be seen
when changing the substance into another
substance. Examples: Flammability, production
of a gas, and the ability to rust or tarnish.
6. •Characteristics that can be seen without
making any changes to the substance?
•Characteristic that can be seen when changing
the substance into another substance?
•Flammability?
•Density?
•Hardness?
•Rust or tarnish?
•Production of a gas?
•Color?
•Phase?
Physical
Chemical
Chemical
Physical
Physical
Chemical
Chemical
Physical
Physical
7. Element: a substance that cannot be broken down into
smaller substances by ordinary chemical means. It is a
pure substance, made up of only one kind of atom.
Atom: The basic particle from which all elements are
made.
Molecule: two or more atoms that are chemically
bonded to form a larger particle.
8. Compound: two or more elements combined
chemically in definite proportions. The properties of
the compound are different from the properties of
the elements that make up the compound.
Mixture: combination of two or more elements or
compounds, which are NOT combined chemically, and
NOT in definite proportions. Each substance keeps its
own properties.
9. Types of Mixtures:
•Heterogeneous Mixture: you can easily see the
different substances.
•Homogeneous Mixture: it is so evenly mixed,
that you can NOT see the different substances that
make it up. A solution, such as stirring sugar into
your tea or the air in our atmosphere, is an
example.
10. •A substance made of only one type
of atom?
•Two or more substances, which are
NOT combined chemically, and NOT
in definite proportions?
•Two or more atoms that are
chemically combined?
•The basic particle from which all
elements are made?
•Two or more elements combined
chemically in definite proportions?
Element
Mixture
Molecule
Atom
Compound
11. Physical Change: You have the same substance
both before and after a physical change. The object
changes in size, shape, or form. (Note: a change in
phase is a physical change.)
12. Chemical Change: A change in the composition of
materials creating a new substance with totally new
properties. (You cannot get the old substances back.)
13. Law of Conservation of Matter: matter cannot be created or
destroyed in a physical or chemical change.
14. Energy Changes: All changes in matter, physical
and chemical, also include a change in energy.
Examples:
•Thermal Energy: this is all of the energy of all of
the particles in an object.
•This is the most common change in energy
when you have a change in matter.
•Temperature is used to measure the average
energy of the motion of particles in an object.
•The flow of thermal energy will always be from
warmer objects to cooler objects.
15. •Two types of thermal change:
oEndothermic: energy is taken in or absorbed. (The
matter being changed absorbs the heat so it feels cold.)
oExothermic: energy is given off or released. Combustion
is an example. (The matter feels warm or hot.)
Temp drops
16. •Chemical Energy: this is energy stored in
the bonds that hold the atoms of a substance
together. When a chemical change occurs,
bonds are broken and new bonds form. Energy
is released in the process.
17. •Electromagnetic Energy: this is energy that
travels through space as waves. Examples:
visible light, microwaves, and x-rays.
•Electrical Energy: this occurs when
electrically charged particles (electrons)
move from one location to another.
18. Indicators of a Chemical Change:
•Gas Liberation: a gas is formed and you observe bubbles
•Heat and/or Light is Given Off: usually observed as
burning
•Color Change: the substance changes to a different color
•Precipitate Forms: solid particles form in a liquid and
sink to the bottom of the container.
