Chemistry

Compound

A unique substance that forms when two or more elements combine chemically. They are held together by chemical bonds.

Compare and Contrast compounds, elements, and molecules

A compound in two or more elements chemically bonded together while a molecule is two or more of one element chemically bonded together. An element is what both are made up of.

What is a pure substance

A definite and constant composition and can either be an element or a compound

How are the properties of a compound different from an element

Elements in a compound combine and become an entirely different substance with its own substances

Chemical Bond

A force of attraction between atoms or ions. Forms when atoms transfer or share electrons. Valence electrons are the key.

ionic bond

The force of attraction that holds together positive and negative ions. Formed between nonmetals and metals

Covalent Bond

The force of attraction that holds together two atoms that share a pair of valence electrons. Nonmetals. Connected to nuclei

Octet Rule

Atoms tend to gain, lose, or share electrons in order to acquire a full set of valence electrons

why are hydrogen and oxygen atoms more stable when they form bonds in a water molecule

By sharing their valence electrons they can get their full outer shell.

Chemical reaction

A process in which some substances turn into different substances with properties that are different than the original substances

How can u tell whether a change in matter is caused by a chemical reaction

Gas formation, Solid formation, color change, odor produced, energy change

How do reactants change into products during a chemical reaction

Reactants break chemical bonds and then the atoms rearrange to form products

What is the law of conservation of mass

Mass cannot be created or destroyed during a chemical reaction

Exothermic reaction

more energy is released when bonds form in products than is used when bonds breaking the reactants

Why are the products of an exothermic reaction likely to be warmer than the reactants

the energy produced in an exothermic reaction is released as heat, it results in a rise in temperature

What is an endothermic reaction

More energy is used to break the bonds in the reactants than is released when bonds form in prodicts

Why are the products of an endothermic reaction likely to be colder than the reactants

the reactants absorb heat energy from their surroundings

how is more energy conserved in an endothermic reaction

it takes more energy to break bonds than is released when new bonds form

what is activation energy

the amount of energy needed to start a chemical reaction

why do reactants need energy in order for a chemical reaction to begin

the reactants must be moving to break the bonds

reaction rate

how fast a chemical reaction occurs

what are things that influence the rate of a chemical reaction

increase in temperature, increase in concentration, increase in surface area, catylasts

What are things that dont influence the rate of a chemical reaction

inhabitors

what is a catylast

a substance that speeds up rate of reaction without being permantantly changed

how does a catylast speed up a chemical reaction

temporarily bonds with reactants which brings them together

synthesis

Reaction in which two or more substances combine to form a single compound

decomposition

Reaction in which a single compound breaks down to form two or more simpler substances

single replacement

Reaction in which an element takes the place of another element that is part of a compound.

Double Replacement

Reaction in which ions in two compounds switch places

Combustion

Reaction in which a flammable substance reacts quickly with oxygen gas releasing energy in the form of light and heat.