Mixtures and pure substances can be categorized and separated using various physical properties. Mixtures are combinations of substances that are not chemically combined and can be separated through processes like distillation or filtration. Solutions are homogeneous mixtures that appear and distribute uniformly. Suspensions and colloids are heterogeneous mixtures where particles settle or scatter light differently. Elements are pure substances made of only one type of atom that cannot be broken down further. Compounds are pure substances made of two or more elements chemically bonded together with unique properties.
1. Mixture
• Two or more substances that are not
chemically combined
• All mixtures can be physically separated
• Some ways to separate mixtures
– Distillation-use boiling point
– Magnet-uses magnetism
– Centrifuge-use density
– Filtering-separates large particles from
smaller ones
2. • Ratio of mixtures are not fixed
• Substances keep their identities
• Mixtures can be solid, liquid or gas
• Examples of mixtures
– Chex mix
– Raisin bran
– Pizza
– Mixed nuts
– air
3. Solutions
• Mixture that appears to be a single
substance
• Material is evenly distributed by dissolving
• Material must be soluble (able to dissolve)
• Solute is what is dissolved
• Solvent what the solute is dissolved in
• Water is the universal solvent
4. • Materials that will not dissolve (insoluble)
forms a mixture that is not a solution
• Examples of solutions
– Sodas
– Gasoline
– Ice tea
– Salt water
– Kool aid
5. • In solutions the particles are so small they
never settle out (sink to bottom), can’t
scatter light nor can they be filtered
• Solubility is the ability of substances to
dissolve at a given temperature and
pressure
• How much of a solute a solvent can hold
is the concentration (grams of
solute/milliliter of solvent, g/mL)
6. • To increase solubility you can increase
temperature, crush, stir, shake
• Homogenous solutions– meaning the
same
• Heterogenous solutions– meaning
different
7. Suspensions
• Suspensions are mixtures where the
particles are heavy enough to settle out
(sink to bottom) of the solution, scatter
light, can be filtered
• Examples of suspensions
– Snow globe
– Italian dressing
8. Colloids
• Colloids are mixtures where the particles
are evenly dispersed but are not heavy
enough to settle out, can scatter light,
can’t be filtered
• Examples of colloids
– Mayo
– Whip cream
– pudding
9. Elements
• elements are pure substance that can not
be separated into simpler substances by
physical or chemical means
• Pure substance is a substance with only
one type of particle called atoms
• All atoms of an element are identical
regardless of how much you have
10. • Elements can be identified by their
characteristic properties
• The properties, both chemical and
physical, do not depend on the amount of
the element present
• Elements can have similar properties but
each element has some property that
makes it unique (density)
11. • Elements are classified by categories
• Metals – shiny, good conductors
• Nonmetals – dull, poor conductors
• Metalloids –has properties of metals and
nonmetals depending on conditions
• Categories allow unknown elements to be
placed in the periodic table based on
similar properties
12. Compounds
• Pure substance composed of two or more
elements that are chemically combined
• Compounds are formed by elements
reacting or having a chemical change
• A particle of a compound is a molecule
• Elements do not form compounds
randomly
• All compounds are formed from only the
elements on the periodic table
13. • Compounds form in specific mass ratio
• Ex: mass of hydrogen to mass oxygen in
water is hydrogen 1 to oxygen 8 which can
be written as 1:8. For every molecule of
water, the ratio is the same, if the ratio is
different, then the compound can not be
water
14. • When elements form compounds, new
characteristics properties are created
• Compounds have properties that differ
from the elements that formed them
• Na (sodium) reactive alkali metal + Cl
(chlorine) poisonous gas → NaCl (table
salt)
15. • Some compounds can be broken down into their
elements by a chemical change
• Other compounds break down into simpler
compounds instead of elements
• The only way to separate a compound into
elements or other compounds is by a chemical
reaction which allows for a chemical change
• Examples: add or take way energy or electric
current
