Chemical Reactions Flashcards
valence electrons determines3
- how reactive element is
- hat elements it will react with
- either lose or gain to form bonds
lewis structure
shows only valence electrons
chemical bond2
- force of attraction that holds 2 atoms together
- held together by negative and positive charges
ion
-atom that has electric charge
cation2
- positive
- loses electron
anion2
- negative
- gains electron
polyatomic ion2
- made of more than one atom
- can be positive or negative
ionic bond6
- when atoms gain or lose valence electrons
- opposites attract, + and - hold it together
- occur between metals (left) and nonmetals (right)
- intend to attain a gull outer shell (2 or 8)
- atoms with 1-4 v.e. will lose
- atoms with 4-7 v.e. will gain
oxidation number3
- the electric charge an atom has after it gains/loses electrons
- charges balance each other (should equal 0)
- little - or + in top after chemical symbol
subscripts2
- ratio of elements in compound
- little number in bottom after chemical symbol
coefficients2
- amount of a compound present
- big number before chemical symbol
covalent bond4
- when 2 atoms share electrons
- formed between atoms of nonmetals
- share electrons to get a full outer shell
- number of bonds on atom can form equals number of electrons needed to make 8
double bond
atoms share 2 pairs of electrons
triple bond
atoms share 3 pairs of electrons
molecular compound3
- composed of covalent bonds
- low melting points
- do not conduct electricity
polar bond3
- some atoms pull more strongly on shared electrons
- makes one side more negative and other more positive
- why water sticks together
non polar bonds2
- shared electrons pulled equally
- no charge on either side
reactant
atom or molecule that go into a chemical reaction and interact (left side of equation)
product
new atoms and molecules that are produced from a chemical reaction (right side of equation)
precipitate
a product of chemical reaction that is a soild
evidence for chemical reactions4
- color change
- solid (precipitate) appears
- gas appears
- change in energy
exothermic reaction3
- releases heat
- temp increases because releases thermal energy
- small arrow, big arrow
endothermic reaction3
- absorbs heat
- temp decreases because thermal energy turns into chemical energy
- big arrow, small arrow
activation energy
minimum amount of energy needed to start a chemical reaction
controlling chem reactions using surface area
when solid is broken into smaller pieces, reaction happens faster
controlling chem reactions using temperature
when temperature increases, reaction happens faster
controlling chem reactions using concentration
when there is more concentration (amount of a substance in a given volume), reaction happens slower because there are more particles to reaction. product may also be different
controlling chem reactions using catalysts
when there are more catalysts (material that lowers activation energy), increases rate of reaction
controlling chem reactions using inhibitors
when there are more inhibitors, reaction happens slower
Ex: food preservatives
synthesis2
to put together
a+b–> ab
decomposition2
to break apart
ab–>a+b
single replacement2
to take place of
ab+c–>a+bc
double replacement2
to trade places
ab+cd–>ac+bd
diff between coefficients and subscripts
coefficients can be changed, subscripts can’t
