unit 2 Flashcards
what is evidence of a chemical change
1)change is colour
2) formation of a gas
3) formation of a precipitate
4) release/absorption of heat
5) difficult to reverse
what is a chemical change
a change in which a new substance is formed
what is collision reaction theory
-chemical reactions involve collisions and rearrangements of atoms or groups of atoms
-the outcome depends on the energy and orientation of the collisions
why do we balance equations
-to obey the law of conservation of mass
why do we balance equations
-to obey the law of conservation of mass
what is the law of conservation of mass
must have same number of atoms on each side of equation
what are the five types of reactions
1) synthesis
2) decomposition
3) combustion
4) single displacement
5) double displacement
what is a synthesis reaction
-two or more reactants combine to produce a new compound
what is a decomposition reaction
a compound breaks down into two or more simpler compounds or elements
what is a combustion reaction
-the rapid reaction of a substance with oxides and energy
-hydrocarbon + oxygen —> carbon dioxide + water + energy
what is an incomplete combustion reaction
-occurs when oxygen supply is limited
-may involve the release of carbon monoxide, carbon, carbon dioxide, soot (C8H), water, and energy
what is a single displacement reaction
-one elements takes the place of another element in a compound
-metal only takes place of metal and non-metal only takes place of non-metal
-metal will only displace a metal listed below it on the activity series
what is double displacement
-the cations and anions of an aqueous solution rearrange
-neutralization is a double displacement
what are the three possible outcomesof a double displacement reaction
-production of a precipitate
-production of a gas
-production of water
define solute
-the substance that dissolves in a solvent
