Chemistry Terms and Concepts

Matter

  • anything that has mass and takes up space

  • Mass - measure of the amount of matter

  • Volume - amount of space a substance occupies

  • Element - pure substance whose atoms all have the same number of protons

  • Atom - smallest unit of an element that maintains the properties of that element

  • Compound - substance that is made from the atoms of 2 or more elements chemically bonded together

  • Molecule - smallest particle of a compound that retains all of the properties of the compound

Properties of Matter

  • 2 types of properties:

    • Extensive properties - depend on the amount of matter present (volume, mass, energy)

    • Intensive properties - don’t depend on the amount of matter present (melting point, density, conductivity, ductility)

Physical Properties

  • characteristic that can be observed or measured without changing the identity of the substance

  • Melting point - temperature at which a substance melts from solid to liquid

  • Boiling point - temperature at which the vapor pressure of a liquid equals the atmospheric pressure; substance becomes a vapor or gas

Physical Change

  • change in a substance that does not involve a change in its identity is a physical change

  • Molecules remain intact; properties of the element or compound are maintained

  • ex. grinding, cutting, melting, freezing, boiling, vaporizing

Phrases of Matter: Solid

  • Solid - definite volume and definite shape

  • Atoms are in a tightly packed structure

  • Particles have little energy and movement

Liquid

  • Liquid - definite volume but an indefinite shape

  • Liquids take the shape of their container

  • Particles are close to each other but can move past each other

Gas

  • Gas - has neither definite volume nor definite shape

  • expand to fill their container

  • Particles have a great deal of energy and move very quickly

  • Particles are far apart from each other

Plasma

  • high temperature state of matter in which atoms lose their electrons

  • ex. the sun is a plasma

Bose-Einstein Condensate (Extra)

  • Very cold low energy state where most of the particles are all in the same quantum state

Chemical properties

  • relates to substance’s reactivity (its ability to undergo changes or reactions that alter it into a different substance)

  • ex. Iron or copper combining with oxygen to form rust or tarnish

Chemical Reaction

  • Chemical change happens through a process called a chemical reaction

  • In a chemical reaction, 1 or more substances are converted into different substances

  • ex. Peach spoiling as sugars change, milk going sour, wood burning

Chemical Reaction

  • The substance or substances that go into the reaction are called reactants

  • The substance or substances that are formed are called products

Mixtures

  • blend of 2 or more kinds of matter

  • may be homogenous or heterogeneous

  • Homogeneous mixtures - uniform throughout and are called solutions

  • Heterogeneous mixtures - different composition in different parts of the mixture

Pure substances

  1. Every sample of a given pure substance has exactly the same characteristics

  2. Every sample of a given pure substances has exactly the same composition