chapter 19 test review physical science

Chemical reaction

A change in which one or more substances are converted into new substances

Reactants

The starting substances that react in a chemical reaction

Products

The new substances produced from a chemical reaction

Chemical equation

A way to describe a chemical reaction using chemical formulas and other symbols

Coefficient

Represent the number of units of each substance taking part in a reaction

Balanced chemical equation

A chemical equation with the same number of atoms of each element on both sides of the arrow

Mole

The amount of a substance that contains 6.02 × 10²³ particles of that substance

Molar mass

The mass (g) of one mole of a substance

Combustion reaction

A reaction in which a substance reacts with oxygen to produce heat and light

Synthesis reaction

A reaction in which two or more substances combine to form another substance

Decomposition reaction

A reaction in which one substance breaks down, or decomposes, into two or more substances

Single-displacement reaction

A reaction in which one element replaces another element in a compound

Double-displacement reaction

A reaction in which the positive ion of one compound replaces the positive ion of the other compound to form two new compounds

Precipitate

An insoluble compound that comes out of a solution during a double displacement reaction

Oxidation

The loss of electrons during a chemical reaction

Reduction

A gain of electrons during a chemical reaction

Exergonic reaction

• Chemical reactions that release energy

• Require less energy to break bonds than is released when new ones are formed

Exothermic reaction

When energy is given off primarily in the form of thermal energy — also exergonic reaction

Endergonic reaction

Chemical reactions that require more energy to break bonds that is released when new ones are formed

Endothermic reaction

When the energy needed to keep a reaction going is in the form of thermal energy

Identical to

The energy released in the formation of a compound from its elements is always ___ the energy required to decompose that compound into its elements

carbon dioxide, water, heat

The main products from methane burning

exergonic, Exothermic

The burning of wood in a campfire that produces heat and light would be both an ____ and an ____ reaction.

Exothermic

If the heat of reaction is negative, the reaction is _____.