Physical vs. Chemical Changes
Types of Chemical Reactions
Counting Atoms
Balancing Chemical Equations
Content Knowledge
100
Is water boiling a physical or chemical change?
Physical
100
A + B -> AB
Synthesis (Addition) reaction
100
How many hydrogen atoms are in H2O?
2
100
Balance this chemical equation
H2 + O2 -> H2O
2H2 + O2 -> 2H2O
100
What side of a chemical equation are the products on?
right
200
Is bread being toasted a physical or chemical change?
Chemical
200
2H2O -> 2H2 + O2
Decomposition reaction
200
How many carbon atoms are in CO2?
1
200
Balance this chemical equation
CH4 + O2 -> CO2 + H2O
CH4 + 2O2 -> CO2 +2H2O
200
What are the names of the little numbers on elements in chemical equations?
subscripts
300
Is Iron rusting a physical or chemical change?
Chemical
300
Single replacement reaction
300
How many nitrogen atoms are in 3N2?
6
300
Balance this chemical equation
C2H5OH + O2 -> CO2 + H2O
C2H5OH + 3O2 -> 2CO2 + 3H2O
300
True or false
Exothermic: Energy is being absorbed
Endothermic: Energy is being released
False!
400
Can a physical change be undone?
Yes
400
C2H4 + 3O2 -> 2CO2 + 2H2O
Combustion Reaction
400
On the right side of this unbalanced equation, how many oxygen atoms are there?
CaCl2 + 2NaHCO3 -> 2NaCl + CaCO3 + CO2 + H2O
6
400
Balance this chemical equation
HCl + NaOH → NaCl + H2O
It is already balanced
400
How many types of chemical reaction are there?
Five
500
List 3 indicators that a chemical change is taking place.
Heat, light, production of a gas, color change, and the formation of a precipitate
500
BaCl2 + Na2SO4 → BaSO4 + 2NaCl
Double replacement reaction
500
On the reactants side of the equation, how many hydrogen atoms are there?
2C6H14 + 19O2 -> 12CO2 + 14H2O
28
500
Balance this chemical equation
C3H8 + O2 → CO2 + H2O
C3H8 + 5O2 -> 3CO2 + 4H2O
500
What is the law of conservation of mass?
The number of atoms on the reactants (left) side of a chemical equation will be the same on the products (right) side of the equation.