Major Points and Concepts
- Matter:
- matter- what the universe is composed of
- two characteristics of matter:
- has mass
- occupies space
- three states of matter:
- solid- rigid; has a fixed volume and shape
- liquid- has a definite volume and takes the shape of its container
- gas- has no fixed volume or shape, so it takes the volume and shape from its container
- Physical and Chemical Properties/Changes:
- two types of physical properties:
- intrinsic- color, odor, density, boiling point
- extrinsic- mass, volume, length
- chemical changes:
- a change that causes a substance to become a new substance or broken down into simpler parts
- physical changes:
- a change that does not change the identity of the substances
- Elements and Compounds:
- elements- pure substances that cannot be broken down into; examples: iron, oxygen, copper
- compounds- a substance made of atoms of different elements bonded together; examples: H2O, CO2
- Mixtures and Pure Substances:
- mixture: materials that have variable composition and are not chemically bonded
- two types of mixtures:
- homogeneous- have equal parts throughout
- heterogeneous- contains regions that have different proportions
- pure substance- always have the same composition; either elements or compounds
- Separation of Mixtures:
- distillation- a method that uses the concept of heating solutions to separate the different liquids and some solids
- filtration- the process of separating liquid from a solid
Example Calculations and Problems
Identifying Homogeneous and Heterogeneous Mixtures:
- fruit salad-- heterogeneous, because there are unequal porportions
- cake batter-- homogeneous, because the ingredients are mixed together to the point
- how to separate sand and water- filtration
- how to separate salt water- distillation (the water evaporates, leaving the salt)
- copper is melted *physical
- iron combines with oxygen to form rust *chemical
- wood is burnt *chemical
- a glass is broken into small pieces *physical
- water is freezes to become ice *physical
- gasoline *homogeneous mixture
- water *pure substance
- brass *pure substance
- air *homogeneous mixture
- cake *heterogeneous mixture
Online Resources
Homogeneous v.s. Heterogeneous Mixtures & Pure Substances
Chemical v.s. Physical Change
An Inside Look at Distillation
Chemical v.s. Physical Change
An Inside Look at Distillation