CHEMICAL EQUATIONS TEST REVIEW
1. IDENTIFYING ELEMENTS BY THEIR SYMBOL.
H₂O
C₆H₁₂O₆
CO₂
H₂O₂
WHICH ELEMENT IS FOUND IN ALL THE COMPOUNDS? _____________
______O which is Oxygen_________________________________________________
2. LIST AND COUNT THE NUMBER OF ATOMS FOR EVERY ELEMENT BELOW.
C₆H₁₂O₆
H₂O
H₂O₂
CO₂
C= 6
H= 2
H= 2
C= 1
H= 12
+O= 1
+O= 2
+O= 2
3 atoms
4 atoms
3 atoms
+_O= 6_
24 atoms
3. HOW MANY TOTAL ELEMENTS and TOTAL ATOMS ARE IN EACH CHEMICAL EQUATION?
C₆H₁₂O₆
H₂O
H₂O₂
CO₂
3 ELEMENTS
2 ELEMENTS
2 ELEMENTS
2 ELEMENTS
C= 6
H=2
H= 2
C= 1
H= 12
+O= 1
+O= 2
+O= 2
+O= 6
3
4
3
24
4. LABEL THE REACTANTS AND PRODUCTS. ARE THE FOLLOWING EQUATIONS BALANCED? TO
FIND OUT, COUNT THE ATOMS OF EACH ELEMENT ON EACH SIDE OF THE ARROW.
P + O2 → P4O10
reactants products
Mg + O2 → MgO
reactants products
P= 1
P= 4
O= 2
O= 10
NOT BALANCED
Mg = 1
Mg = 1
O=2
O=1
NOT BALANCED
5. DRAW A MODEL WITH CIRCLES OF THE FOLLOWING COMPOUNDS.
FILL IN THE CIRCLES TO REPRESENT H₂O.
6. TEARING PAPER IS AN EXAMPLE OF A ___PHYSICAL__ CHANGE.
7. BURNING PAPER IS AN EXAMPLE OF A __CHEMICAL__ CHANGE.
8. FREEZING, MELTING AND BOILING WATER ARE ALL EXAMPLES OF _PHYSICAL__ CHANGES.
9. EXAMPLES OF A _CHEMICAL_______ CHANGE ARE……………………….
A. BUBBLES OR GAS IS FORMED
B. COLOR CHANGES
C. FORMING A PRECIPITATE (TWO LIQUIDS FORM A SOLID)
D. WHAT ELSE COULD GO HERE? _ENERGY_________________
10. THE LAW OF CONSERVATION OF ENERGY SAYS THAT CHEMICAL EQUATIONS MUST BE
BALANCED. IF THERE ARE 2 OXYGENS ON THE LEFT SIDE WE MUST HAVE __2___OXYGENS ON
THE RIGHT SIDE. WHICH MEANS MASS HAS BEEN CONSERVED OR SAVED.
IF THERE ARE 2 OXYGEN ON THE LEFT, AND 4 OXYGEN ON THE RIGHT, IS THE EQUATION
BALANCED? ___No, as the law of conservation of mass states that the mass must equal on both
sides of the equation in order for it to be conserved (saved/same)________________ Explain
why or why not in complete sentences.
11.
C= 3
C= 1
H= 8
H= 2
O= 1
O= 1 + 2 = 3
C3H8 + 10O → 4H2O + 3CO2
NOT BALANCED
12.
C= 1
C= 1
H= 4
H= 2
O= 2
O= 3
NOT BALANCED
CH4 + 2O2 → C02 + 2 H20
DETERMINE IF THE ABOVE CHEMICAL EQUATIONS ARE BALANCED OR NOT. THEN BALANCE IT
IF NEEDED. SHOW YOUR WORK in a separate sheet of paper.
13. COMPLETE YOUR
C
= unexpected Color
E
= Energy (light, sound, heat)
G = Gas (bubbles)
S = Solid formation (when two
liquid combine and form a solid, also
known as a precipitate)ACRONYM/NOTES.