Intro to chem

Matter
Whatever occupies space and can be perceived by our senses
The law of conservation of mass
The total mass remains constant during a chemical change
Physical change
A change in the form of matter but not its chemical identity
Chemical change/reaction
A change in which one or more kinds of matter are transformed into new matter
Physical property
A characteristic the can be observed without changing its chemical identity
Chemical property
A characteristic of a material involving its chemical change
Substance
A kind of matter that cannot be separated into other kinds of matter by any physical process
Element
A substance that cannot be decomposed by any chemical reaction into a simpler substance
Compound
A substance made up of two or more elements chemically combined
Law of definite proportions
A pure compound, whatever its source, always contains definite proportions of the elements by mass
Mixture
A material that can be separated by physical means
Heterogeneous
Each part of the mixture can be differentiated from one another
Homogeneous (solution)
A mixture that is uniform in its properties throughout given samples
Sig. Figs
The digits in a measured number that are certain, plus one have some uncertainty
Density
Mass per unit of volume
Dimensional analysis
A conversion method from one unit to another