CHEMISTRY MEMORIZATION:
STEPS FOR SOLVING STOICHIOMETRY
PROBLEMS: MEMORIZE THESE use these till they are in your dreams!!!
1. Complete reaction, determine the compounds,
check oxidation numbers of each compound for
correctness.
2. Balance the equation
3. Set up the Dimensional analysis problem:
a.) Decide what you know about the materials.
b.) Decide what you want to find out.
c.) Put the given and the unknown in the
appropriate places.
4. Always use the units in all conversion factors,
a.) The top of each factor will match the bottom of
the next factor until you reach the desired unit.
b.) In the mole to mole conversion factors the
coefficients of the balanced equation
provides the conversion mole ratio numbers.
c.) For gram conversions, the periodic table
provides the mass of the substance.
5. For other mole conversions:
a.) Remember 1 mole =6.022 x 1023 representative
particles
b.) 1 mole = 22.4 L of any gas at STP (Standard gas
Temperature (0oC)& Pressure (1atmosphere))
6. Do the math, multiply the numerator values &
divide by the denominator values, simplify
7. ALWAYS write the unit and the compound of your
answer.
Ex: 1N2(g) + 3H2(g)  2NH3(g). If 4.00 mol of H2 react, how many moles of NH3 will be produced? Find
given, find unknown: 4.0mol
are the requested units correct?
MOLE TO MOLE STOICHIOMETRY [answer]
You must balance all equations before doing the stoichiometry.
1. How many moles of magnesium are required to react completely with 5.0 moles of nitrogen gas?
Mg]
_Mg + _N2  _Mg3N2
2. How many moles of oxygen are required to produce 3.60 moles of Iron(III) oxide?
_FeS + _O2  _Fe2O3 + _SO2
3. Calculate the moles of Calcium from 5.8 moles of aluminum nitride.
_AlN + _Ca  _Ca3N2 + _Al
[15 mol
[12.6 mol O2]
[5.8 mol Al]
4. What is the minimum number of moles of oxygen required to produce one mole of carbon dioxide? [0.5 mol
CO2] _CO + _O2  _CO2
5. When 5.7 moles of sulfur tetroxide decompose, how many moles of sulfur are produced?
_SO4  _S8 + _O2
[8.55 mol O2]
6. How many moles of water are needed in this cationic displacement to react exactly with 2.0 moles of
Calcium? [4.0 mol HOH] _Ca + _H2O  ____ + ____
7. What is the total number of moles of sodium hydroxide needed to neutralize 2.0 moles of sulfuric acid?
[4.0 mol NaOH ] _NaOH + _H2SO4  ____+ ____
8. What is the total number of moles of hydrogen produced when 4.0 moles of sodium react completely?
[2.0 mol H2] _Na + _H2O  ____ + ____
9. How many moles of lead (II) sulfate are formed when 0.150 mole of aluminum sulfate is reacted? [0.225 mol
PbSO4] _PbCl2 + _Al2(SO4)3  _____ + _____
Ex:_ 2KClO3(s)  2KCl(s) + 3O2(g). What mass of KClO3 do you need to produce 0.500 mol O2? Find
given, find unknown: 0.500 mol
are the requested units
correct?
MOLE TO GRAM STOICHIOMETRY
Be sure to balance all equations before doing the Stoichiometry.
1. What mass of oxygen is produced by the decomposition of 3.00 moles of water?
_H2O  ____ + ___
[48.0gO2]
2. How many grams of Hydrogen are needed to produce exactly one mole of ammonia?
_N2 + _H2  _NH3
[3.0molH2]
3. How many grams of oxygen will combine with 3.00 moles of Manganese to produce Manganese (IV) oxide?
[94gO2] _Mn + _O2  __
4. Iron metal reacts in moist air by oxidation to give a hydrated iron (III) oxide. Calculate the mass of Iron (III)
oxide produced by the reaction of .010 mole of iron.
[0.798gFe2O3]
_Fe(s) + _O2(g)  ___
5. At read heat, copper metal and oxygen react to form copper (I) oxide. How many grams of copper (I) oxide at
may be produced by oxidizing to red heat 10.0 moles of copper?
[715gCu2O]
_Cu(s) + _O2  __
6. Calculate the number of grams of aluminium oxide produced when 2.50 moles of aluminium are burned in
oxygen. [127gAl2O3]
_Al + _O2  __
7. Sulfur burns in air to form the gaseous sulfur dioxide. How many grams of sulfur dioxide are produced when
4.8 moles of sulfur are burned?
[2.460x103gSO2]
_O2 + _S8  ___
8. At elevated temperatures (red heat), the trioxide molybdenum (VI) oxide, is formed. How many grams of
molybdenum burn with 5.7 moles of oxygen gas? [365gMo]
_Mo + _O2  ___
9. Determine the number of moles of chlorine gas needed to bubble through sodium bromide aqueous solution to
yield 9.6 moles of sodium chloride and the precipitate bromine.
[340gchlorine gas]
·
Ex:_ 2Al2O3  4Al + 3O2_
given, find unknown:
How many moles of aluminum will be produced from 30.0 kg Al2O3? Find
check, did you find the unknown? Are the units
correct.
GRAM TO MOLE STOICHIOMETRY
Balance all equations before doing the stoichiometry.
1. How many moles of carbon dioxide are produced when 30.0 grams of ethane (C2H6) are burned completely?
[0.50molCO2] _C2H6 + _ O2  _CO2 + _H2O
2. How many moles of lead (II) sulfate are formed when 367 grams of aluminium sulfate react?
[8.95molPbSO4]
_PbCl2 + _A12(SO4)3  _PbSO4 + _AlCl3
3. How many moles of hydrogen are generated by passing hot steam over 625 g of iron, which oxidizes to form
magnetite, iron (II,III) oxide (Fe3O4) , in the following equation.
[14.9molH2]
_Fe(s) + _H2O(g)  _H2(g) + _Fe3O4(s)
4. Calculate the moles of potassium chloride required to produce 56 grams of chlorine gas in this anionic single
displacement.
[1.58molKCl] _KCl(aq) + _I2(aq)  _ + _
5. Phosphorus is formed by heating tetraphosphorus decoxide in the following reaction: What mass of P4O10 must
be reduced to produce 3.25 mol of phosphorus?
[]
_P4O10(s)  _P4(s) + _
6. How many moles of aluminum will be produced from the decomposition reaction of 30.0 kg aluminum oxide?
[589mol Al] _Al2O3  __ + __
7. How many moles of silver nitrate will be displaced by 95.8 grams of copper producing copper (II) nitrate?
[3.01mol AgNO3]
_Cu + _AgNO3  _____ + ____ observe at http://www.youtube.com/watch?v=Y3Dcv_QnQzk
8. How many moles of cadmium sulfide that can be made from the double displacement of 5.00 mg of sodium
sulfide? [6.40x10-5molCdS] _Na2S + ___Cd(NO3)2  ____ + _____
9. In the double displacement reaction 92.0 grams of Nickel(IV) cyanide precipitates; with many moles of
Nickel(IV) nitrate?
[0.565mol Ni(NO3)4] __KCN + __ Ni(NO3)4  ____ + ____
Ex:_ Methane burns in air by the following reaction: 1CH4(g) + 2O2(g)  CO2(g) + 2H2O(g)
What mass of water is produced by burning 500. g of methane?
GRAM TO GRAM STOICHIOMETRY
Be sure to balance all equations before doing the Stoichiometry
1. How many grams of carbon dioxide are produced by the combustion of 200.0g of propane (C3H8)?
[598gCO2]
___C3H8 + _O2  ___ + ___
2.
How many grams of oxygen are required to produce1.93g of H2O?
_NH3 + _O2  _NO + _H2O
[5.15gO2]
3.
How many grams of vanadium (III) oxide are required to be completely replaced by 16.3 g of iron?
[65.6gV2O5]
__Fe + __V2O3  ___ Fe2O3 + __ VO
4.
What mass of hydrogen sulfide will combine with 3.0 g of bismuth chloride to produce hydrogen chloride?
[0.486gH2S]
BiCl3 + __H2S  __Bi2S3 + __HCl
5.
75.9g of sodium chloride will precipitate how many grams of iron (III) chloride?
__ NaCI + __Fe(OH)3  __NaOH + __FeC13
6.
If I need 68 g of copper; how many grams of copper (II) sulfate must I react with iron to precipitate iron (III)
2
sulfate? [1.71x10 CuSO4]
__Fe(s) + __CuSO4  __Cu (s) + __ Fe2(SO4)3
7.
Suppose a heap of steel scrap 1650 kg of which 3.19% is iron that rusts within a year. Rusting of iron occurs in
the presence of moisture according to the following equation: __Fe(s) + __O2(g)  __Fe2O3(s)
What
4
mass of iron will the heap have after one year of rusting? [1.58x10 gFe2O3(or 1.58kg)]
8.
How many grams of Fe2O3 will react with 18.97 grams of C in the REDOX reaction below? [1.68x102gFe2O3]
__Fe2O3 + _C  _Fe + _CO2
[70.3gFeCl3]