Transcript Chapter 15/16

Chapter 9
Stoichiometry
I.
Stoichiometry
A. The calculation of quantites in
chemical reactions
B. A recipe of what is happening
C. Interpreting Chemical
Equations
1.
2.
3.
4.
Particles
Moles
Mass
Volume
D. N2 (g) + 3H2(g)  2 NH3 (g)
II. Chemical Calculations
A. Mole-mole calculations
1. How many moles of
ammonia are produced when
0.60 mol of nitrogen reacts with
hydrogen?
2. How many moles of copper
are produced when 0.2 moles
aluminum reacts with copper (II)
sulfate?
B. Mass-Mass Calculations
Calculate the number of grams of NH3
produced by the reaction of 5.40 g hydrogen
with an excess of nitrogen.
N2(g) + 3H2 (g)  2NH3 (g)
Review for quiz
How many grams of calcium metal will react
completely with 10.0 grams of water to yield
calcium hydroxide and hydrogen gas?
Ca + H2O  Ca(OH)2 + H2
A reaction between methane and sulfur produces
carbon disulfide. A) How many moles of CS2 are
produced when 1.50 moles of S8 is used? B)
How many mole H2S is produced?
C. Other Stoichiometric
calculations
1. How many molecules of
oxygen are produced when
a sample of 29.2 g of water
is decomposed by
electrolysis?
2. Assuming STP, how many
liters of oxygen are needed
to produce 19.8 L SO3?
S(g) + O2(g)  S03(g)
Review for Quiz #2
How many molecules of Na2CO3 are
produced from 6.7 g NaHCO3?
NaHCO3 --> Na2CO3 + H2O + CO2
If carbon monoxide reacts with oxygen to
produce carbon dioxide, how many liters
of oxygen are required to burn 3.86 L of
carbon monoxide?
III. Percent Yield
A. Theoretical yield - maximum amount
of product that can be produced from
a given amount of reactant
B. Actual yield - amount of product
actually produced when the
chemical reaction is carried out in
an experiment
C. Percent yield
1. The ratio of the actual yield to the
theoretical yield
2. % yield = actual yield from an exper x100
theore. Yield from calcul.
3. When K2CrO4 is added to a solution
containing 0.500 g AgNO3, solid silver
chromate is formed.
A. Determine the theoretical yield of the
silver chromate precipitate.
B. If 0.455g Ag2CrO4 is obtained, calculate
the percent yield.
D. Limiting Reactants
1. Limiting reactants - used up first,
limits the reaction
2. Excess reactants - left over
reactants
3. Example: Use the reaction below,
identify the limiting reactant
Al +
0.25 mol
O2 --> Al2O3 Find the limiting
.40 mol
reactant.
3.6 mole Al reacts with 5.3 mole Cl2 to
produce aluminum chloride.
c. If 14.5 moles of phosphorus reacts
with 18.0 moles of oxygen to
produce tetraphosphorus decoxide.
d. Sodium reacts with chlorine to
produce sodium chloride.
1. If 6.70 moles of Na reacts with
3.20 of Cl2 what is the limiting
reactant?
2. How many moles of NaCl are
produced?
e. How many grams of aluminum
sulfide can form from the reaction of
9.00g of Al with 8.00g of S?
f. If 40.0 g of H3PO4 react with 60.0g
of MgCO3, calculate
1. Find the limiting reactant
2. How much excess is left over
3. the grams of Mg3(PO4)2 produced
4. the grams of CO2 produced
5. the volume of CO2 produced at
STP