S(ABEKA) CHAP?

Chemical reaction

A chemical change that happens when atoms or molecules collide.

Reactants

The original substances that go through a chemical reaction.

Products

The new substances made by the reaction.

Chemical reactions

Are not reversible.

Evidence of a chemical reaction

Change in color, formation of a gas, formation of a precipitate, release or absorption of energy.

Chemical equation

An expression that uses chemical symbols to show a chemical reaction.

Coefficient

The number before a chemical formula that shows how many molecules or formula units are involved.

Law of Conservation of Mass

The total mass of the reactants equals the total mass of the products.

Balanced chemical equation

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

Combination (synthesis) reaction

Two or more substances combine to form a new substance.

Decomposition reaction

A compound breaks down into different substances.

Single‑displacement reaction

One element replaces another in a compound.

Double‑displacement reaction

Two compounds exchange ions or atoms.

chemical thermodynamics

the study of the relationship between chemical reactions and the laws of thermodynamics

Chemical energy

A form of potential energy that may be released as thermal energy when molecules combine or break apart

first law of thermodynamics

Energy gained of lost by a system (the object or group of objects under study) equals the energy lost or gained by the surroundings (everything outside the system)

exothermic reaction

A chemical reaction that releases thermal energy. (It releases energy in the form of heat)

A heat pack is an example of what reaction?

Example of an Exothermic reaction

Endothermic reaction

A chemical reaction that causes thermal energy to be absorbed and stored in the chemical bond of products

A cold pack is example of what reaction?

Example of an endothermic reaction because the cold pack is absorbing energy form you

second law of thermodynamics

Requires that every chemical reaction must cause a decrease in usable energy and an increase in entropy (disorder)

Spontaneous

able to occur by itself without continuing outside help

Chemical kinetics

the area of chemistry that addresses the rates of chemical reactions

Activation energy

The kinetic energy necessary for molecules to chemically react

Catalyst

A substances that alters the rate of a chemical reaction without being permanently changed in the reaction. (It is not apart of reactions)

Reversible reaction

A reaction that under the right conditions can be made to go backward

chemical equilibrium

Both reactions occur at the same rate

Le Chatelier's Principle

The principle stating when a system at equilibrium is disturbed the system will react to at least partially offset that disturbance

Salt

any ionic compound that does not contain a hydrogen ion or hydroxide ion

Acid

Any substance that produces hydrogen cations (H+) when dissolved in aqueous solution

Base

any substance that forms hydroxide anions (OH-) in water

Neutral

Any substance that are nether acids nor basses: a neutral substance does not produce H+ or OH- when dissolved in water

Oxonium ions (hydronium ions)

H3 O+ ion formed by H+ ions attaching themselves to water in an aqueous solution

A substance that produce oxonium ions

(Acid)

Strong acids

completely dissociate to form oxonium ion and another ion

Weak acids

only partially dissociate to form ions

Strong bases

Bases that completely dissociate or react to form hydroxide ions (OH-) when dissolved in aqueous solution

Weak bases

only partially ionize in solution to produce hydroxide ions

Neutralization reaction

A reaction that occurs when a strong acid reacts with a strong base

pH

A scale that indirectly represents oxonium concentration using powers of 10

Buffer

A solution that resists changes in pH because it contains a weak acid and one of its basics salts or a weak base and one of its acidic salts.