Matter and Energy Characteristics of Matter and Calculations in Chemistry

Chemistry

is the study of matter and the changes it undergoes.

Matter

is anything that occupies space and has mass.

Substance

Has definite composition and distinct properties.

Mixture

Combination of 2 or more substances. It can be created and then separated by physical means into its pure component without changing the identities of the components.H

Homogeneous

the composition is uniform throughout the mixture.

Heterogeneous

the composition is not uniform throughou the miture.

Element

Cannot be separated into simpler substances by chemical means.

Compound

Composed of atoms of two or more elements chemically into their pure composition. They can be separated only by chemical means into their pure components.

Solid

Molecules are held close together in an orderly fashion with little freedom of motion.

Liquid

Molecules in this state are close together but are not held so rigidly in position and can move past one another.

Gas

In this state, molecules are separated by distances that are large compared with the size of the molecules.

Physical Property

Can be measured and observed without changing the composition or identity of a substance

Intensive

does not depend on the amount of substance present, Example: color, odor, taste, density, boiling point and melting point.

Extensive

depends on the amount of substance present, Examples: mass, volume, length.

Chemical Property

Observed during a reaction in which the chemical composition or identity of the substance is changed.

Heat of combustion

energy released during combustion, ΔHc.

Chemical Stability

whether a compound will react with water or air.

Flammability

whether a compound will burn when exposed to flame.

Chemical Reaction

is a process in which a substance (or substances) is changed into one or more new substances. To represent chemical reaction chemical equation is used, uses chemical symbols to show what happens during a chemical reaction. A chemical equation is a shorthand method of representing chemical reaction using chemical symbols and formulas to indicate the reactants and the products.

Reactants

are the starting materials in a chemical reaction and product is the substance formed as a result of a chemical reaction. In a chemical equation, the reactants are conventionally written on the left and the products on the right of the arrow.

Combination Reaction

also known as a synthesis reaction, is a reaction where two or more elements or compounds (reactants) combine to form a single compound (product).

Decomposition Reaction

a compound breaks down into two or more simpler substances

Displacement Reaction

more active metal can displace a less active metal, while a less active one can’t displace the more active.

Metathesis Reaction

Double Displacement Reaction, the positive ions exchange partners with the negative ions to form two new compounds.

Neutralization Reaction

an acid and base quantitatively react together to form a salt and water as products

Combustion Reaction

reaction of elements and compounds with oxygen.

Stoichiometry

is a term used to describe quantitative relationships in chemistry. It is the quantitative study of reactants and products in a chemical reaction.