Chemical Equations and
Equation Stoichiometry Review
1. A sample of magnesium carbonate is heated.
a) Write a balanced molecular equation for this reaction (include phases) and indicate
the type of reaction:
If exactly 4.75 g of the magnesium carbonate is heated,
b) Calculate the mass of gas produced:
c) Calculate the volume of gas produced at STP:
d) Calculate the number of gas molecules produced:
e) Calculate the mass of the other product:
f) Calculate the mass of magnesium carbonate that must be heated to produce 75.0L of
the gas at STP:
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2. When nitrogen gas reacts with oxygen gas to produce nitrogen dioxide gas, 33.2 kJ of
heat is absorbed per mole of nitrogen dioxide .
a) Write a BME for this reaction and include phases and the energy term:
b) What class of reaction is this:
c) Identify substance oxidized and substance reduced:
If one was to produce 200.0 g of nitrogen dioxide gas,
d) Calculate the masses of nitrogen and oxygen gases needed to react produce this
amount of gas:
e) Calculate the energy involved in the reaction in (d):
f) Calculate the volumes of nitrogen and oxygen gases, measured at STP, needed to
produce 200.0 g of nitrogen dioxide:
g) Calculate the volume the nitrogen dioxide would occupy at STP:
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3. A sample of potassium metal is placed in water.
a) What class of reaction is this?
b) Include phases for:
BME:
CIE:
NIE:
c) Identify substance oxidized and substance reduced:
If exactly 0.220 g of potassium reacts with excess water,
d) Calculate the mass of gas produced:
e) Will the resulting solution conduct electricity? Explain.
f) If the solution is allowed to evaporate, calculate the mass of solid left:
g) Calculate the mass of water needed to react with the 0.200 g of potassium:
h) If the reaction releases 3750 kJ per mole of potassium reacted, calculate the amount
of heat released when the 0.200 g of potassium reacts with the water:
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4. Aqueous solutions of iron(II)chloride and sodium hydroxide are mixed:
a) Include phases for:
BME:
CIE:
NIE
b) What class of reaction is this?
If 3.20 g of the iron(II) chloride reacts with 1.75 g of the sodium hydroxide:
c) Determine the limiting reactant:
d) Calculate the mass of precipitate formed:
e) Calculate the mass of excess reactant left over:
f) If 2.50 g of precipitate is actually collected, calculate the percent yield:
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5. A sample of gaseous butane, C4H10, is burned in air. The reaction releases 2430 kJ per
mole of butane.
a) What class or reaction is this?
b) Write a BME and include the phases and energy term:
If exactly 500.g of butane reacts with 1.200 X 103 liters of oxygen gas at STP,
c) Determine the limiting reactant:
d) Calculate the mass of carbon dioxide produced:
e) Calculate the mass of water produced:
f) Calculate the mass of excess reactant that remains:
g) Calculate the number of molecules of excess reactant:
h) Calculate the amount of heat released:
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6. Equal volumes of equal concentrations of sulfuric acid and sodium hydroxide are mixed.
The reaction has ∆H = -53.3 kJ/mol acid. Write the following and include phases:
a) BME:
b) CIE:
c) NIE:
d) Classify reaction:
If exactly 49.0 g of sulfuric acid reacts with sufficient sodium hydroxide,
e) Calculate the mass of water formed:
f) Name the salt formed:
g) Calculate the mass of the salt formed:
h) Calculate the mass of sodium hydroxide reacted:
i) Calculate the amount of heat involved in the reaction:
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7. A sample of lithium chlorate is heated.
a) Write a BME and include phases:
b) Classify reaction:
If 1.20 g of the lithium chlorate is heated,
c) Calculate the mass of salt formed:
d) Calculate the mass of gas produced:
e) Calculate the volume of gas produced:
f) Calculate the number of gas molecules produced:
g) The salt formed does not conduct electricity in the solid phase but will conduct electricity
when dissolved in water. Explain:
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8. A sample of molten (liquid) potassium chloride undergoes electrolysis.
a) Write a BME and include phases:
b) Classify reaction:
c) Calculate the mass of salt that must be electrolyzed to produce 95.0 L of the product
gas at STP:
d) If 55.0 g of the potassium chloride is electrolyzed, calculate the mass of solid product
formed:
e) If 24.6 g of the solid is actually obtained in part (b), calculate the percent yield:
f) In a separate electrolysis, 90.0 L of the gas was collected at STP. If this represents a
77.5% yield, calculate the mass of potassium chloride that had to be electrolyzed to
produce 100% yield.
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