Matter exists in three main phases; solid, liquid, gas. These phases can be changed depending on how much energy the given matter has (solid being the least and gas being the most amount of energy).
Matter is a very broad category and matter can be very different from other matter depending on how it is arranged chemically.
Matter that contains only one kind of particle.
Some examples would be: oxygen, water, gold, carbon dioxide, etc.
Matter that contains more than one kind of particle.
Some examples would be: steel (an alloy of iron and carbon), air (contains nitrogen, oxygen, carbon dioxide, argon, and more), salt water, etc.
A pure substance that cannot be broken down into simpler parts by chemical methods.
Some examples would be: helium, iron, argon, neon, lithium, etc.
A pure substance made of two or more different elements that are chemically combined.
Some examples would be: carbon dioxide, glucose, water, sodium chloride (table salt), etc.
A characteristic of a substance that can be observed and measured without changing the identity of the substance.
Some qualitative properties include: colour, odour, texture, lustre, etc.
Some quantitative properties include: viscosity, melting point, boiling point, density, etc.
The measure of a substances resistance to flow.
Liquids with a high viscosity flow slowly and vice-versa.
Water would be an example of a liquid with a low viscosity, while molasses would be an example of a liquid with a high viscosity.
The temperature at which a solid turns into a liquid (and a liquid can turn back into a solid).
Melting is when a solid turns into a liquid, and solidification is when a liquid turns into a solid.
Different substances can have radically different melting points such as helium with a melting point of -272.2 degrees Celsius and water at 0 degrees Celsius.
The temperature at which a liquid turns into a gas (and a gas can turn back into a liquid).
Evaporation is when a liquid turns into a gas, and condensation is when a gas turns into a liquid.
Boiling points can be radically different as well, as shown be helium at -269 degrees Celsius and water at 100 degrees Celsius.
A measure of the ability of a substance to dissolve in another substance.
Solubility is recorded as the maximum amount of a substance/solute that can dissolve into another substance/solvent; the units are expressed as a concentration, usually units are: mass of solute per mass of solvent, or mass of solute per volume of solvent.
An example would be sodium chloride which has a solubility of 39.5g/100mL in water at 25 degrees Celsius and atmospheric pressure.
The ratio of the mass of a substance to the volume it occupies.
Solids generally are the densest, followed by liquids, and finally gases. However, different elements and compounds can have very different densities even in the same phase of matter.
The ability of a substance to change (react) and form new substances.
Different elements and compounds have different reactivity with other different substances.
Some important kinds of chemical reactivity on earth include: reactivity with water, oxygen, acids, and another pure substance.
The ability of a substance to burn in air.
Propane is a compound that has a high combustibility and releases a large amount of heat when burned.
The ability of a substance to remain unchanged.
When scientists are trying to synthesize new elements they can have issues stabilizing them so that they do not radioactively decay into another element.
The ability of a substance to cause harmful effects in plants and animals.
Almost all chemicals are poisonous at high enough concentrations; even oxygen can kill you if you are exposed to too much.
Toxicity is usually expressed as a LD50 value. This unit of measure refers to the dose required to kill 50% of the exposed population.