Gen Chem 1 (Chapter 1)

Chapter 1 vocabulary from macmillan

What is chemistry?

The study of matter and its changes

Scientific Method

Cyclical process of formulating and testing ideas

Hypothesis

An observation that can be tested and experimented

Theory

Tested explanation of an observation or experimental result, well supported with evidence (explains behavior)

Law

Describes or predicts what will happen. It does not explain why, but what (described behavior)

Matter

Anything that has mass and takes up space (volume)

Composition

What something is made up of and how it’s arranged (the building blocks of matter: atoms, molecules, ionic compounds, covalent compounds)

Atoms

The smallest unit of life (the number of protons that makes up a compound)

Molecules

Made up of 2 or more atoms

Element

Substance that is made up of one type of atom (all elements we know are on the periodic table)

Compound

Substance that is made of more than one type of atom in a fixed ratio

Diatomic

two atoms of an element pair

Mixture (homogeneous)

More than one substance is evenly blended (salt and water)

Mixture (heterogeneous)

components are not evenly blended (oil and water)

Difference between mixture and compound

Mixtures can be separated without substance changing, but compounds cannot be separated without changing the substance into their elemental forms

3 states of matter

Solid, liquid, gas

Solid

Has definite shape and volume

Liquids

Have definite volume but no definite shape (takes the shape of containers)

Gas

Has no definite volume or shape (takes the shape of containers)

Melting

solid to liquid

Boiling (vaporization)

liquid to gas

Sublimation

Solid to gas

Freezing

liquid to solid

Condensation

gas to liquid

deposition

gas to solid

Physical properties

Characteristics we can measure without changing the substance’s identity (color, temperature, mass, volume, shape, melting point, boiling point, etc) ex. gold, water

Physical changes

Changes that occur without a change in the substance’s identity (includes melting, freezing, boiling)

Chemical properties

Characteristics that cannot be measured or observed without a change in identity (including flammability and reactivity with other substances)

Chemical changes

Substance becomes a different substance upon heating or other reactions (compounds break apart or rearrange)

Potential energy

energy that is stored (plant grow by absorbing energy from the sun)

energy that is released (fire releases stored energy converting plant material back into CO2 and H2O)

Kinetic energy

energy of motion

Exothermic charge

Releases heat energy (wood burning)

Endothermic change

Absorbs heat energy (heat to boil water)