Stoichiometric Relationships

Elements

Substances composed of one or more types of atoms, with over 100 known elements, and the smallest unit being an atom.

Compounds

Substances formed by chemically combining two or more elements in fixed ratios, exhibiting unique properties different from their component elements.

Mixtures

Combinations of elements or compounds not chemically bonded, retaining individual properties, with homogeneous mixtures having uniform composition throughout.

Solid state

State of matter with fixed shape and volume, particles held by intermolecular forces, and transitions to gas by sublimation or liquid by melting.

Liquid state

State with fixed volume but takes the shape of the container, transitioning to solid by freezing or gas by boiling/vaporization/evaporation.

Gaseous state

State filling the container, particles widely spaced with negligible forces, transitioning to liquid by condensation or solid by deposition.

Sublimation

solid to gas

Melting

solid to liquid

Freezing

liquid to solid

Boiling

liquid to gas

Condensation

gas to liquid

Deposition

gas to solid

molar mass

• the mass of one mole of any substance

avogadro’s constant

• a single atom of an element has a small mass

relative atomic mass

• weighted mean of all the naturally occurring isotopes of the element

empirical formula

• in simplest whole number the ratio of atoms of each element in a substance

molecular formula

• shows the actual number of atoms in a substance

structural formula

• shows the arrangement of atoms and bonds within a molecule

How many elements

Over 100

Example of mixture

Air

Example of compound

Water

Atom

The smallest part of an element

Solid state

• fixed shape and volume

• particles held together by intermolecular forces

• particles will vibrate at a fixed point but do not have translational velocity

Liquid state

• fixed volume

• takes up the shape of the container

• held together by intermolecular forces

Gaseous state

• takes the space to completely fill container

• widely spaced particles

• intermolecular forces between particles are negligible

• pressure is due to gaseous particles colliding with the walls of the container