chemical formula
a group of chemical symbols and numbers that represent the elements and the number of atoms of each element that make up a compound
Exs: NaCl, HOH, CO, H2O2, NaOH, HCl
chemical equation
A representation of a chemical reaction that uses symbols to show the relationship between the reactants and the products
reactants
Elements or compounds that enter into a chemical reaction. Found on the LEFT side of the arrow.
products
The elements or compounds produced by a chemical reaction; the NEW substances formed during a chemical reaction. Found on the RIGHT side of the arrow.
coefficients
The big numbers found in front of a chemical formula in an equation. In a chemical equation- it represents the relative amounts of a substance taking part in a reaction. In other words- it shows how many molecules of a given formula are present.
Exs: 2NaC
subscripts
Numbers written below the line that tells how many atoms of a given type are in a compound. They are the small numbers written to the lower right of an element's symbol.
law of conservation of mass
The principle that the total amount of matter is constant during any physical or chemical change (matter is neither created nor destroyed during these types of changes).
balanced equation
A chemical equation in which mass is conserved; each side of the equation has the same number of atoms of each element.
synthesis reaction
A+B-->AB
a type of chemical reaction where two or more chemicals combine to form a more complex product. Also called direct combination.
example of SYNTHESIS
A+B-->AB
Decomposition
AB --> A + B
a type of chemical reaction in which one compound breaks down and forms two or more substances
example of DECOMPOSITION
AB->A+B
Single Replacement
A + BC --> B + AC
A reaction in which the atoms of one element replace the atoms of a second element in a compound
example of SINGLE REPLACEMENT
A + BC --> AC + B
Double Replacement
AB + CD = AD + CB
a chemical reaction where two elements in different compounds trade places
example of DOUBLE REPLACEMENT
AB + CD --> AD + CB
Combustion
CH + O2 --> H2O + CO2
a reaction in which a substance reacts rapidly with oxygen, often producing heat and light
example of COMBUSTION
hydrocarbon (fuel) + O2 --> CO2 + H2O
neutralization reaction
H___ + ___OH ---. H2O + salt
the reaction of an acid (starts with H) and a base (ends on OH) to form a neutral solution of water and a salt (any ionic compound)
example of NEUTRALIZATION
acid + base ---> a salt + water