Name ___________________________________ Date ______________________ Class ______________________
Worksheet #1
Chapter 12 – Stoichiometry
Mass to Mass Problems
Now that we understand what mole is (a molar mass of grams, 6.02x1023 atoms/molecules, and 22.4 liters of gas at STP)
and have studied equation writing, we are ready to combine the two ideas. This is called stoichiometry - the method
for calculating amounts of reactants and products in chemical reactions.
First: Write the balanced equation describing the reaction.
Second: Write the given information over its appropriate term in the equation.
Third: Use the process we learned in chapter 10 to solve for the unknown mass.
Example: How many grams of oxygen (O2) would be produced by decomposing 868 grams of mercury (II) oxide (HgO) by
heating strongly?
Example: How many grams of water would be produced by burning 16.0 grams of hydrogen?
Solve the following problems. You must set them up and solve them as shown in the examples. You must show
calculations of the molar mass of each compound. You must circle your final answer.
1. How many grams of oxygen would be produced by the electrolysis of 72.0 grams of water?
𝐷𝐶
_____H2O
→
_____O2 + _____H2
2. How many grams of zinc chloride would be formed if 130.74 grams of zinc reacts?
_____Zn + _____HCl → _____ZnCl2 + _____H2
3. What mass (grams) of copper (II) oxide will be formed if 125 grams of copper reacts?
_____Cu + _____O2 → _____CuO
4. What mass (grams) of oxygen will be released when 250.0 grams of potassium chlorate is thermally decomposed?
∆
_____KClO3 → _____KCl + _____O2
5. What mass (grams) of oxygen would be released by the thermal decomposition of 1255 grams of mercury (II) Oxide?
∆
_____HgO → _____Hg + _____O2
6. What mass (grams) of magnesium chloride would be formed by the complete reaction of 75.0 grams of magnesium?
_____Mg + _____FeCl3 → _____Fe + _____MgCl2
7. What mass (grams) of silver oxide would you need to decompose in order to produce 432 grams of silver?
∆
_____Ag2O → _____Ag + _____O2
8. How many grams of magnesium oxide would be formed if 35.75 grams of magnesium were burned?
∆
_____Mg + _____O2 → _____MgO
9. How many grams of zinc would you need to produce 8.08 grams of hydrogen?
_____Zn + _____H2SO4 → _____ZnSO4 + _____H2
10. What mass (grams) of sodium sulfate would be formed by the complete reaction of 120.0 grams of sodium
hydroxide?
_____NaOH + _____H2SO4 → _____Na2SO4 + _____HOH
11. What mass (grams) of oxygen would you need to completely burn 80.0 grams of methane, CH4?
∆
_____CH4 + _____O2 → _____CO2 + _____H2O
12. How many grams of iron would be produced by the reduction of 325 grams of iron (III) oxide?
∆
_____CO + _____Fe2O3 → _____Fe + _____CO2