Substance, Element, Compound, Mixture
Compound
2 or more elements that are chemically combined in a definite ration
Chemical Property
A characteristic of a substance that can't be observed without altering the substance's composition. The substance changes its identity (a different chemical formula)
What is an easy way to distinguish between a chemical change and a physical change?
A chemical change means a change of chemical formula - it will look and behave differently. A chemical change can't be reversed.
Is changing sates of matter a physical or chemical change?
A physical change since matter doesn't change it's composition.
What are 4 chemical changes that can happen to matter?
Flammability, Reacts with acid, Forms a new solid in liquid, Photosensitivity, Produces a new gas when heated
Can you reverse a chemical change?
No
Example of a Homogeneous Mixture
Saltwater or vinegar
Law of Conservation of mass/matter
The mass of all substances before a physical or chemical change equals the mass of all the substances after the change.
Physical Change
a change in a physical property
Hetergeneous Mixture
a mixture where different materials are spread out unevenly
Homogeneous Mixture
a mixture where substances are universally spread out
Substance
an element or a compound
Physical Property
any characteristic of a substance that you can observe easily without changing the composition of that substance
Example of a Hetergeneous Mixture
bottle of salad dressing
Evidence for a chemical change?
change in color (burned toast) new odor (rotten eggs) energy is released (flames/feel heat) energy is absorbed (cooked) new gases or solids form
Make a list of 8 physical properties matter can have
color, shape, taste, size, odor, temp, height, width
Examples of physical changes that can happen to matter
cut, tear, grind, bend, dissolve
Mixture
material made up of 2 or more substances not chemically combined
Element
matter made up of 1 kind of atom
Chemical Change
the change of one substance into a different substance