Pure substances have a fixed, uniform composition which gives them consistent properties, while mixtures can have varying compositions and properties. Elements are made of single types of atoms, while compounds contain two or more elements in fixed proportions. Mixtures can be either heterogeneous, with observable differences in composition, or homogeneous, appearing uniform throughout. Based on particle size, mixtures can be classified as solutions, suspensions, or colloids.
2. Pure Substances
Every sample of a given substance has the same
properties because a substance has a
fixed, uniform composition.
3. Elements and Compounds
An element has a fixed composition because it
contains only one type of atom.
One capital letter
A compound always contains two to more
elements joined in a fixed proportion.
More than one capital letter
4. The properties of a
mixture can vary
Mixtures because the
composition of a
mixture is not fixed.
Heterogeneous Homogeneous
Comes from the Greek One mixture so thoroughly
words: dissolved in another
mixture that it is hard to
distinguish between the two
Hetero: Different: in the mixture.
Geneous: Kind Ex: salt water.
5. Colloids
Suspensions,
Solutions,
Based on the size of its largest
particles, a mixture can be classified as a
solution, a suspension, or a colloid.
Solution
A homogeneous mixture that does not
separate into layers over time
Can be seen through
Must be separated chemically
6. Colloids
Suspensions,
Solutions,
Based on the size of its largest
particles, a mixture can be classified as a
solution, a suspension, or a colloid.
Suspension
A heterogeneous mixture that separates into
layers
Can be separated physically
7. Colloids
Suspensions,
Solutions,
Based on the size of its largest particles,
a mixture can be classified as a solution,
a suspension, or a colloid.
Colloid
Particles in between solutions and
suspensions.
Do not separate into layers
Cannot be separated by a filter
8. Lava with high Lava with low
viscosity viscosity
Viscosity
• The thickness of a liquid
• The higher viscosity, the thicker the liquid.
12. Flammability
Flammability is a material’s ability to burn in the
presence of oxygen.
The ability to burn is not a physical property
because you cannot observe burning without
changing the composition of the of the material
that is burning.
13. Reactivity
Reactivity is the property that
describes how readily a substance
combines chemically with other
substances.