Matter
What is matter?
Matter is anything that has mass and volume (takes up space). Matter can be classified based on; particle
arrangement, energy of particles and distance between particles. Matter is made of tiny particles called
atoms which are in constant motion (movement).
Note: Water exists in the three states of matter. Water can be ice (solid), liquid(water),
gas(steam)
Mass
Mass is the amount of matter in an object.
• The mass of an object is constant
• Mass is measured with a balance
• Common units for mass are grams and kilograms.
Volume
• Volume is constant for solids and liquids; it varies for gases.
• The volume of an object can be measured in many ways.
For a solid, use formulas like 𝑉 = 𝑙𝑤ℎ or 𝑉 = 𝐵ℎ.
For an irregular solid, use the water displacement method.
For a liquid, use a graduated cylinder.
• Common units for volume include cubic centimeters, milliliters, and liters.
Density
Density is the amount of mass in a given volume.
• It is a derived unit of measure, meaning the measurement is obtained from a combination of two other
characteristics of an object—its mass and volume.
M
• It is equal to mass divided by volume. D=
V
• It is measured in units such as grams per cubic centimeter and grams per milliliter.
Sinking vs. Floating
Objects may sink or float in a liquid.
• Objects sink when their density is the density of the surrounding liquid.
• Objects float when their density is the density of the surrounding liquid.
The states of matter
There are four states of matter solids, liquids, gases and plasma. The three major states of matter are;
solid, liquid and gas.
Particles arrangement in the three states of matter
Properties of states of matter
Physical and Chemical Changes
In our daily life we come across several changes; Dissolving sugar in water, Cooking of food, cutting of a
piece of paper, stretching a rubber band, melting of ice, Burning of wood.
Changes are of two main types; physical change and chemical change.
A physical change is a change in which no new substance is formed. Only the physical properties like
shape, size, state of the substance changes. Example: Cutting of paper into pieces, Melting of ice, Boiling
of water, Stretching a rubber band.
A chemical change is a change in which new substances are formed. A chemical change is also called
chemical reaction. During a chemical change the following can be observed new substances formed, heat
or light absorbed or released, sound may be produced, color change may take place, a gas may be
formed, change in smell may take place. Examples: Rusting of iron, Burning of wood, Cooking food.
Changes of state
A change of state is the change of a substance from one physical form of matter to another.
Is a change of state physical or chemical?
To change a substance from one state to another energy must be added or removed. When you add
energy the particles move faster or move farther apart. When you remove energy the particles slow down
or move closer together.
Mixtures and Pure Substances
All matter can be classified as mixture or pure substance as illustrated on the diagram
Pure Substances
ELEMENTS
Elements are the simplest pure substances. Examples: O-Oxygen, H- Hydrogen, Na- Sodium, C- Carbon,
Fe- Iron
The smallest particle of an element is an atom.
Compounds
Compounds are pure substances that are made of more than one element bound together. Examples: H 2O
and CO2
A molecule is formed when two or more atoms chemically combine.
Mixtures
HOMOGENOUS
In homogeneous mixtures, components cannot be distinguished from each other, appear as one
substance. Particles distributed evenly throughout. Example: air, salt water,
Homogenous mixtures are also called SOLUTIONS
HETEROGENOUS
All components of the mixture are visible because they do not mix together. Particles not distributed
evenly. Example; sand and water, vegetable soup, oil and water
Solutions
A solution is a homogenous mixture in which a solute (usually a solid) is dissolved in a solvent(usually a
liquid)
Example: In salt water,
salt is the solute, gets dissolved. Water is the solvent, dissolves other substance
The substance that looks like it has disappeared is called the solute. The substance that we can still see is
called the solvent. The solvent and the solute together are called solution
Types of solutions
There are 3 types of solutions
o Saturated: Maximum amount of solute dissolved in solvent
o Unsaturated: Less than maximum amount of solute dissolved in solvent
o Supersaturated: More than maximum amount of solute dissolved in solvent
Methods of Mixture Separation
1) Mechanical Separation (often by hand) takes advantage of physical properties such as color and
shape.
2) Magnetic Separation takes advantage of the physical property of magnetism
3) Filtration takes advantage of the physical property of the state of matter. A screen lets the
liquid particles through, but traps the solid particles.
A filter can also be used to separate solid particles of different sizes.
(ex. a window screen, an air filter, a sand sieve)
4) Decanting:
5) To pour off a liquid, leaving another liquid or solid behind. Takes advantage of differences in
density.
6) Distillation: The separation of a mixture of liquids based on the physical property of boiling
point
7) Paper chromatography:
Uses the property of molecular attraction (molecular polarity) to separate a mixture.
Different molecules have varying molecular attractions for the paper (the stationary phase) vs. the
solvent (the mobile phase)
