Worksheets9th grade - Balancing chemical equations
Total questions: 20
Worksheet time: 5hrs 0mins
What does the Law of Conservation of Mass state?
The number of atoms never changes during a chemical reaction
The number of atoms always changes during a chemical reaction
The number of atoms sometimes changes during a chemical reaction
The number of molecules never changes during a chemical reaction
2H2 + O2 --> 2H2O
2H2 + O2 --> 2H2O
3Cr(MnO4)6
Example: H2
Al + O2 --> 2Al2O3
O2
Ex: 2H2 + O2 --> 2H2O
We learned to determine if a chemical equation is balanced
By counting the number of atoms before and after the reaction.
By calculating the molar mass of all the substances involved.
By calculating the moles of all the substances involved.
By dividing the number of atoms by the number of moles for each substance involved
2C2H2 + 5O2 --> 4CO2 + 2H2O
4Fe + 3O2 --> 2Fe2O3
MgCl2 --> Mg4+ Cl2
__ Al + __ HCl → __ H2 + __ AlCl3
__Ag2O →__ Ag +___O2
Select the set of coefficients that balance this equation:
____ KClO3 → _____ KCl+ _____ O2
2, 2, 3
2, 3, 2
3, 2, 2
1, 2, 2
Which set(s) of coefficients balance out this chemical equation (more than one solution possible):
____ Mg + ____ P4 → _____ Mg3P2
6, 1, 2
24, 4, 8
12, 2, 4
18, 3, 6
