Download Chemical Reactions Powerpoint

9/30/2016
•What
is an example of a chemical reaction?
do we represent a chemical reaction by
words?
•Reactants
Products
•How
•Reactant
•
1 + Reactant 2
Product 1 + Product 2
Chemical equations show the kind of reactants
and products and their amounts in a reaction.
4 Al (s) + 3 O2 (g)  2 Al2O3 (s)
•
•
The numbers in front of the chemical formula are
called coefficients
Coefficients tell you how many of each of the
reactants and products are present in the reaction.
•
The letters (s), (g), and (l) are the physical states of
compounds and (aq) means that the compound is
dissolved in water.
4 Al(s) + 3 O2(g)  2 Al2O3(s)
This equation means:
4 Al atoms + 3 O2 molecules –give 2 formula units of Al2O3
(s) = solid (g) = gas (l) = liquid (aq)=aqueous
Because of the law of
conservation of matter,
an
Demo of conservation of matter, See
Screen 4.3.
It must have the same number
of atoms of the same kind on
both sides.
Lavoisier, 1743-1794, with wife
1
9/30/2016
1.
2.
3.
___ Al(s) + ___ Br2(l) ---> ___ Al2Br6(s)
4.

Balance carbon first
Balance hydrogen second
Balance oxygen last
If you cannot balance oxygen (because there is
an odd number) restart the balancing with a
“2” in front of the fuel.
KNO3 + H2CO3  K2CO3 + HNO3
__C3H8(g) + ___ O2(g)  ____CO2(g) + _____ H2O(g)
__B4H10(g) + ___ O2(g) ___ B2O3(g) + ___ H2O(g)
2