Chemical Reactions
Where are reactants located in a chemical equation?
What is the FIRST step to balancing chemical equations?
List/count the elements
Balance the following equation: _____H2 + ____O2 ---> ____H2O
2 H2 + 1 O2 ---> 2 H2O
Balance the following chemical equation:
___ C + ___ S8 ---> ___ CS2
4 C + 1 S8 ---> 4CS2
What type of reaction is:
2 H2 + 1 O2 ---> 2 H2O
Synthesis
Where are the products located in a chemical equation?
On the right.
Which part of a chemical equation can you change to balance?
Coefficients
Balance the following Equation: _____KClO3 ---> KCl + ______O2
2 KClO3 ---> 2 KCl + 3 O2
Balance the chemical equation:
__ Li + __ H2O ---> ___ LiOH + ___ H2
2 Li + 2 H2O ---> 2 LiOH + 1 H2
A handful of aluminum strips are dropped into a beaker of copper (II) chloride solution. What type of reaction occurs?
Single replacement
What is the difference between a coefficient and a subscript?
Coefficients = how many molecules we have, subscripts = how many atoms we have in a molecule
If you don't add a coefficient in front of a molecule, you have _______ of that molecule.
One
Balancing chemical equations:
____ N2 + ____ H2 ----> ____ NH3
1 N2 + 3 H2 --> 2 NH3
A student reacts calcium nitrate and sodium chloride. What type of reaction is this?
Double replacement
What does the law of conservation of mass state?
The law of conservation of mass states that matter durning a chemical change can neither be created nor destroyed.
Which molecule should you balance LAST in this equation? O2 + CH4 --> CO2 + H2O
Oxygen, because it is alone and won't affect other elements when you change the coefficient of O2.
Balance the following equation: ____P + _____O2 --->_____P2O5
4 P + 5 O2 ---> 2 P2O5
Balance the following chemical equation: ___ N2 + ___ O2 ----> ___ N2O5
2 N2 + 5 O2 ----> 2 N2O5
What type of reaction is an acid/base neutralization, like one seen in the following reaction.
H2SO4 + 2NaOH ---> Na2SO4 + 2H2O
Double replacement
Identify the NAMES of the reactants and products in the following chemical equation: H2SO4 + 2NaOH ---> Na2SO4 + 2H2O
Reactants: sulfuric acid and sodium hydroxide
Products: sodium sulfate and water
Why do we balance chemical equations?
Because of the Law of Conservation of Mass.
Balance the following equation: ____C3H8 + _____O2 ---> ____CO2 + ____H2O
1 C3H8 + 5 O2 ---> 3 CO2 + 4 H2O
Balance the following chemical equation:
____ C2H6 + ___ O2 ---> ____ CO2 + ____ H2O
2 C2H6 + 7 O2 ---> 4 CO2 + 6 H2O
This reaction occurs in cars to make them move, using gasoline (a hydrocarbon) and oxygen gas as reactants.