Module 1 Definitions

For Chemistry

Matter

Anything that has mass and occupies space

Law of Conservation of Matter

Amount of matter existing = constant (aka can’t destroy or create matter)

Energy

the ability to move or to do work

Law of Conservation of Energy

amount of energy = constant (energy can’t be destroyed or created)

Kinetic Energy

Molecular Motion (associated with Temperature)

Absolute zero

Zero Molecular Motion (coldest temperature possible)

Potential Energy

energy stored in chemical structure (Energy Associated with composition)

Accuracy

How close a value is to the actual (true) value

Precision

How close a set of values are to each other (when actual (true) value is not taken into account

Physical properties

one we can observe without changing the chemical identity of a substance.

Chemical properties

a characteristic of matter that can only be observed and measured by performing a chemical reaction or chemical change.

Extensive properties

dependent on the amount of matter

Intensive properties

Independent of the amount of matter

Compound

2 or more different elements held together by chemical bonds

Homogeneous Mixture

Same proportion of its components throughout the sample

Heterogeneous mixture

mixture in which the composition is not uniform throughout

Atom

The smallest unit of a chemical element (defined by # of protons)

Molecule

2 or more atoms held together by chemical bonds

Heat

the amount of energy transferred from one system to its surroundings due to chemical differences

Temperature

Average kinetic energy of all atoms or molecules of that substance

Specific Gravity

The ratio of the density of a substance to the density of water