Chapter 4 – Elements,
Compounds, and Mixtures
Section 1 – Elements
ELEMENTS
• Pure substance that cannot be separated into simpler
substances.
• Made up of atoms
• Simplest form of matter
• Ex: Carbon (C), Helium (He), Oxygen (O)
PROPERTIES
• Elements have a unique set of properties.
• Ex: boiling point, density, reactivity with acid,
flammability
• Used to classify elements.
– Grouped into categories
– Elements in same group have shared properties
3 CATEGORIES
3 CATEGORIES
3 CATEGORIES
Chapter 4 – Elements,
Compounds, and Mixtures
Section 2 – Compounds
COMPOUNDS
• Composed of two or more elements that are
chemically combined.
• Two or more atoms join together to form molecules.
• Must undergo a chemical change.
• Most substances are compounds, few elements are
found alone in nature.
PROPERTIES
• Each compound has a unique set of properties just
like elements.
• Compounds have different properties than the
elements that they are made of.
• Can be broken down into elements or simpler
compounds through chemical changes.
Chapter 4 – Elements,
Compounds, and Mixtures
Section 3 – Mixtures
MIXTURES
• Made of two or more substances
– Any combination of elements, compounds, or both
• NOT chemically combined
– No chemical change occurs
– No change to substances identity
• Examples: salt water, steel, air, cereal, pizza,
chicken soup
2 Kinds of Mixtures
• Homogeneous mixture – every sample of
the mixture is the same
– Examples: salt water, flat soda
• Heterogeneous mixture – not every sample
of the mixture is the same.
– Examples: chicken soup, pizza, salad dressing.
SEPARATING MIXTURES
• By physical change
• Examples: sorting, filtering, heating, cooling
SOLUTIONS
• Has an even distribution of particles throughout the
mixture
– Homogeneous mixture
– Examples: salt water, kool-aid
• Formed by dissolving solute into solvent
– Solute – the substance that is dissolving
– Solvent – the substance that the solute is dissolving in
PROPERTIES OF SOLUTIONS
• Concentration – measure of the amount of solute
dissolved in a solvent.
– Concentrated – solution has more solute
– Dilute – solution has less solute
• Saturation – how much solute a solvent can hold
– Unsaturated – solution can hold more solute
– Saturated – solution has all the solute it can hold
PROPERTIES OF SOLUTIONS
• Solubility – amount of solute needed to form a
completely saturated solution.
– Changes for each substance as temperature changes
SUSPENSIONS
• Particles are large enough to separate themselves
from a solvent based on density.
– Insoluble – particles not able to dissolve
– Heterogeneous mixture
– Examples: chicken soup, salad dressing.
COLLOIDS
• Particles are small enough to mix with a solvent but
not large enough to separate out.
• Heterogeneous mixture
• Properties of both solutions and suspensions
– Spreads out like a solution
– Does not dissolve like a suspension
• Examples: JELL-O, fog, mayonnaise