ch 8: chemical equations

chemical equations

shorthand notation for chemical changes or reactions

s

solid (written after substance)

l

liquid (written after substance)

g

gas (written after substance)

aq

substance dissolved in aqueous solution

Λ

heat is added (above or below reaction arrow)

law of conservation of mass

the total mass of substances in a chemical reaction must remain constant

double displacement reactions

two compounds exchange partners with one another to yield two new compounds

decomposition reactions

a single reactant breaks down into two or more products

single displacement reactions

one element (A) reacts with a compound (BC) to replace one element in the compound, giving a new element (B) and a different compound (AC)

heat of reaction

quantity of heat actually produced during a chemical reaction

exothermic reactions

release heat

endothermic reactions

absorb heat

endothermic reactions

heat can be treated as a reactant

exothermic reactions

heat can be treated as a product

products

higher potential energy than reactants

activation energy

amount of energy needed to initiate a chemical reaction