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.