Name: _____________________________________________
Worksheet – Chemical Equations
1. In a chemical equation, the reactants are always on the __left___________________. While the products are always
on the ___right_____________________________.
2. Give the symbol used in a chemical equation to represent the following physical states.
a. solid _(s)____
b. liquid _(l)___
c. gas __(g)___
d. aqueous _(aq)__
3. Briefly describe the purpose of a catalyst in a chemical reaction.
A catalyst lowers the amount of energy needed for the reaction to occur.
4. Briefly describe a balanced chemical equation.
A chemical equation where coefficients have been added so there are the same number of atoms of each element on
the reactant and product sides of the chemical equation. Follows the Law of Conservation of Mass.
5. Balance the following equations.
a. __2___ Fe + ___3__ H2SO4 → _____ Fe2(SO4)3 + __3___ H2
b. _____ SnO2 + __2___ H2 → _____ Sn + __2___ H2O
c. _____ SeCl6 + _____ O2 → _____ SeO2 + __3___ Cl2
6. Define a mole and its importance in going from a balanced chemical equation to performing the chemical reaction in
a laboratory.
A mole is 6.02 x 1023 atoms or molecules. When writing a chemical equation on a piece of paper, the coefficients
represent the number of atoms/molecules. However, in a laboratory we cannot weigh out single atoms or molecules.
We need to bring the scale of the chemical equation to a level we can measure in the laboratory. By using a mole as
the count of the atoms or molecules, the number of atoms or molecules is large enough to weigh in the laboratory.
For example, the mass of 1 Carbon atom (12 amu) is 2.0 x 10-23 grams, while the mass of 1 mole of Carbon atoms is 12
grams.
7. Calculate the molar mass of the following compounds.
a. K2SO4 ______________
2K
2 x 39 = 78
1S
1 x 32 = 32
4 Oxy 4 x 16 = 64
174
b. Ca3(PO4)2 ______________ c. CH3CH2CO2H _______________
3 Ca 3 x 40 = 120
2 P 2 x 31 = 31
8 Oxy 8 x 16 = 128
279
3 C 3 x 12 = 36
6H 6x1= 6
2 Oxy 2 x 16 = 32
74
8. Do the following conversions.
a. 6.5 moles NaOH = ____________ grams NaOH
1 mole NaOH = 40 g NaOH
6.5 moles NaOH x
40 𝑔 𝑁𝑎𝑂𝐻
1 𝑚𝑜𝑙𝑒 𝑁𝑎𝑂𝐻
= 260 g NaOH
b. ___________ moles NaOH = 257 grams NaOH
1 mole NaOH = 40 g NaOH
257 g NaOH x
1 𝑚𝑜𝑙𝑒 𝑁𝑎𝑂𝐻
40 𝑔 𝑁𝑎𝑂𝐻
= 6.43 moles NaOH