molar mass of compounds - edl. molar mass of compounds summary & review 1. what does the...
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Outline of Topics
1. Molar Mass of Compounds2. Moles Grams & Grams Moles
3. Balancing Reactions4. Mole Ratios5. 1-Step & 2-Step6. Limiting Reactants7. Percentage Yield
1. Molar Mass of Compounds
1 + 2(3 + 4) =
What does it mean to submerge?
Where does a submarine go?
What does “sub” mean?
1. Molar Mass of Compounds
OBJECTIVE:
Calculating molar mass of
compounds like NaCl, H2O,
Mg(OH)2
1. Molar Mass of Compounds
Where do you find the molar
mass of each element?
1. Molar Mass of Compounds
Get the molar mass of CO
C: 1
O: 1
x 12 = 12
x 16 = 16
1. Molar Mass of Compounds
Get the molar mass of CO2
2 = SUBscript
tells us how many
C: 1
O: 2
x 12 = 12
x 16 = 32
1. Molar Mass of Compounds
Get the molar mass of Ca3P2
Ca: 3
P: 2
x 40 = 120
x 31 = 62
1. Molar Mass of Compounds
Get the molar mass of H2O
H: 2
O: 1
x 1 = 2
x 16 = 16
1. Molar Mass of Compounds
Get the molar mass of Ca3(PO4)2
Ca: 3
P: 2
O:8
x 40 = 120
x 31 = 62
x 16 = 128
1. Molar Mass of Compounds
1. List elements2. Write how many of each element
3. Get molar mass of each element
4. Get total
1. Molar Mass of CompoundsSummary & Review
1. What does the subscript tell us?
2. What happens when there is a
parenthesis?
3. Calculate the molar mass for the
following
Na3N CaCl2 PCl3H2O2 N2O4 NaNO3
Na2SO4 Mg(OH)2 (NH4)2SO4
2. The Mole and Molar Mass
How many eggs in a dozen?
How many flowers in a dozen?
If you 2 dozen roses for your valentine, how many roses did you buy?
If one rose costs $3.27, how much did you spend just on flowers?
2. The Mole and Molar Mass
OBJECTIVE: converting
grams to moles
2. The Mole and Molar Mass
a DOZEN of _____ = 12
a MOLE of something is equal to
602000000000000000000000or
6.02 x 1023
Avogadro’s Number
2. The Mole and Molar Mass
1 MOLE of eggs = 602000000000000000000000 eggs
1 MOLE of donuts = 602000000000000000000000 donuts
1 MOLE of flowers = 602000000000000000000000 flowers
1 MOLE of O atoms = 602000000000000000000000 Li atoms
2. The Mole and Molar Mass
How calculate GRAMS MOLES
Molar Mass : 1 mol
2. The Mole and Molar MassHow calculate GRAMS MOLES
How many moles are in 24 grams of C?
24 g 1 mol =12 g
2. The Mole and Molar Mass
How calculate GRAMS MOLES
How many moles are in 327 g of NaCl
Na: 1 x 23 g = 23 g+ Cl: 1 x 35 g = 35 g
NaCl = 58 g
327 g NaCl 1 mol NaCl58 g NaCl 5.64 mol NaCl
2. The Mole and Molar Mass
How calculate GRAMS MOLES
How many moles are in 327 g of Ba3(PO4)2
Ba: _ x 137 g = P: _ x 31 g =
+ O:__ x 16 g = Ba3(PO4)2 = _______ g
327 g Ba3(PO4)2
2. The Mole and Molar Mass
How calculate MOLES GRAMS
How many grams are in 5.600 mol of NaCl?
Na: 1 x 23 g = 23g+ Cl: 1 x 35 g = 35g
NaCl = 58 g
5.600 mol NaCl 58 g NaCl
1 mol NaCl= 324.8 g NaCl
2. The Mole and Molar Mass
How calculate MOLES GRAMS
How many grams are in 5.600 mol of BaCl2?
Ba: 1 x 137 g = 137 gCl: 2 x 35 g = 70 g
BaCl2 = 207 g
5.600 mol BaCl2 207 g BaCl2
1 mol BaCl2
= 1159.2 g BaCl2
2. The Mole and Molar Mass
How calculate GRAMS # of atoms
How many atoms are in 327 g of Ba3(PO4)2
Ba: _ x 137.33 g = P: _ x 30.97 g =
+ O:__ x 16 g = Ba3(PO4)2 = _______ g
327 g Ba3(PO4)2
2. The Mole and Molar Mass
Convert the moles into grams
1. 2.26 mol of NO2
2. 5.8 mol of PCl53. 2.26 mol of CaCl2Convert the grams into moles
4. 50 g of NO2
5. 58 g of PCl56. 2.26 g of CaCl2
7. 2.26 mol of carbon dioxide into grams
8. 2.26 grams of dihydrodenmonoxide into mol
2. The Mole and Molar Mass
Convert the moles into grams
1. 2.26 mol of CO2. 5.8 mol of SF6
3. 1.5 mol of Ca3P2
4. 1.2 mol of NaOH5. 2.5 mol of
Ca(OH)2
6. 3.27 mol of Cu(NO3)2
Convert the grams into moles
1. 32 g of CO2. 58 g of SF6
3. 327 g of Ca3P2
4. 20 g of NaOH5. 20 g of Ca(OH)2
6. 20 g of Cu(NO3)2
2. The Mole and Molar Mass
1. 2.26 mol of carbon dioxide2.2.26 mol of dihydroden monoxide
3. 55 grams of ionic compound sodium oxide
4. 55 grams of ionic compound calcium chloride
2. The Mole and Molar Mass
Summary & Review
1.One mole of a compound is equal to its m____ m___
2.Strategy for setting up gram mole conversions
3. Balancing Reactions
Write a math problem, any problem
3. Balancing Reactions
OBJECTIVE:Writing chemistry
equations like a recipe
3. Balancing Reactions
H2 + O2 H2O
reactants “equals” productsyields
produces
3. Reactions
Show chemical changes with equations
Reactants Products
means “produces”
3. Balancing Reactions
H2 + O2 H2O
subscripts = # of atoms
3. Balancing Reactions
COEFFICIENTS
2H2 + O2 2H2O
coefficients = how many MOLES
3. Balancing Reactions
2H2 + O2 2H2O
subscripts = # of atomscoefficients = how many
3. Balancing Reactions
2H2 + O2 2H2O
Law of Conservation of MassNeed same number of atoms on
both sides of
3. Balancing Reactions
“BALANCE” the reaction by adding COEFFICIENTS
H2 + O2 H2O2H2 + O2 2H2O
3. Balancing Reactions
NEVERbalance by adding subscripts
2H2 + O2 2H2O
H2 + O2 H2O2
4. Balancing Reactions
frame + wheels + chain + handlebars + pedals 1 bicycle
1 frame + 2 wheels + 1 chain + 1 handlebar + 2 pedals 1bicycle
What are those numbers?
COEFFICIENTS
4. Balancing Reactions
2H2 + O2 2H2O
NEVER change subscripts
3. Balancing Reactions
1. Na + O2 Na2O2
2. C + S8 CS2
3. Al + S8 Al2S3
4. CO2 + H2O O2 + C6H12O6
5. Na + NaNO3 Na2O + N2
6. H3PO4 + KOH K3PO4 + H2O7. C3H8 + O2 CO2 +H2O8. NH3 + O2 N2 + H2O (fractions?)
9. C2H6 + O2 CO2 + H2O (fractions?)
1. NH4OH + H3PO4 (NH4)3PO4 + H2O
2. H3PO4 + Mg(OH) 2 Mg3 (PO4)2 + H2O
3. Al(OH)3 + H2SO4 Al2(SO4)3 + H2O
4. C10H22 + O2 CO2 + H2O (fractions?)
1. NH4OH + H3PO4 (NH4)3PO4 + H2O
2. H3PO4 + Mg(OH) 2 Mg3 (PO4)2 + H2O
3. Al(OH)3 + H2SO4 Al2(SO4)3 + H2O
4. C10H22 + O2 CO2 + H2O (fractions?)
5. Al + HAsO3 H2 + Al(AsO3) 3
(fractions?)
1. C2H6 + O2 CO2 + H2O
2. Al + HAsO3 H2 + Al(AsO3) 3
3. H3PO4 + Mg(OH) 2 Mg3 (PO4) 2 + H2O
4. NH4OH + H3PO4 (NH4)3PO4 + H2O
5. Al(OH)3 + H2SO4 Al2(SO4)3 + H2O
6. C10H22 + O2 CO2 + H2O (fractions?)
3. Balancing ReactionsStrategy
1. What does the subscript tell you?
2. What do the coefficients tell you?
3. Which of the above is used when balancing reactions?
1. Ni(ClO3)2 NiCl2 + O2
2. AgNO3 + AlCl3 AgCl + Al(NO3)3
3. NH3 + CuO N2 + Cu + H2O
4. (NH4)2Cr2O7 Cr2O3 + N2 + H2O
5. C4H10 + O2 H2O + CO2
3. Balancing ReactionsStrategy
1. Pick a compound that only appears once.
2. NEVER split compounds,
NEVER3. Leave elements (H2, O2, Cl2 Al, Fe, Zn)
until the end
4. Practice is the only way
4. Mole Ratio
set up 3 and 5 as a fraction
set up 7 and 2 as a fraction
set up 2 and 3 as a fraction
4. Mole Ratio
OBJECTIVE: another step to add to your sideways T
4. Mole Ratio
2KI + Pb(NO3)2 PbI2 + 2KNO3
COEFFICIENTS = # of MOLES
KI = 2 moles
Pb(NO3)2 = 1 mole
PbI2 = 1 mole
KNO3 = 2 moles
4. Mole Ratio
2KI + Pb(NO3)2 PbI2 + 2KNO3
COEFFICIENTS = # of MOLES
You start this reaction with 10 mols of KI. How many mols
of PbI2 is produced?
solve by using sideways t
4. Mole Ratio
2KI + Pb(NO3)2 PbI2 + 2KNO3
COEFFICIENTS = # of MOLES
You start this reaction with 10 mols of Pb(NO3)2. How many mols of PbI2 is produced?
solve by using sideways t
4. Mole Ratio
2KI + Pb(NO3)2 PbI2 + 2KNO3
COEFFICIENTS = # of MOLES
You need to produce 10 molsof KNO3. How many mols of
Pb(NO3)2 do you need?
solve by using sideways t
2H2 + O2 2H2O
You have 3 moles of O2
How many moles of H2O can you produce?
You have 3 moles of H2
How many moles of H2O can you produce?
4. Mole Ratio
1. 2Na + Cl2 2NaCl5 moles of Na = ? moles NaCl?
2. CH4 + 2O2 CO2 + 2H2O2 moles of O2 = ? moles CO2?
3. Cu + 2AgNO3 2Ag + Cu(NO3)24 moles of AgNO3 = ? moles Ag?
4. 2KI + Pb(NO3)2 PbI2 + 2KNO343 moles of KI = ? moles PbI2?
4. Mole Ratio
Summary & Review
1. What do the coefficients tell you?
2. How can you tell that your sideways T is setup correctly?
3. Fe2O3 + 2Al →2Fe + Al2O3
You have 3.30 mol of Fe2O3. How
many moles of Fe?
4. Mole Ratio
2H2 + O2 2H2OYou have 64 grams of O2
How many moles of H2O can you produce?
How do you solve something like this?
1. Calculate Molar Mass2. Grams Mol3. Mole Ratio
5. Stoichiometry HWY
OBJECTIVE:Molar Mass + Mole Ratio
5. Stoichiometry HWY
What are we doing?Using reactions like recipies
5. Stoichiometry HWY
4. Balancing Reactions
H2 + O2 H2O
reactants “equals” products
Reactants Products
means “produces”
4. Balancing Reactions
frame + wheels + chain + handlebars + pedals 1 bicycle
1 frame + 2 wheels + 1 chain + 1 handlebar + 2 pedals 1bicycle
What are those numbers?
COEFFICIENTS
5. Stoichiometry HWY
To get from this side of
the arrow
To this side
You need the
MOLE RATIO
C6H8O7 + 3NaHCO3 → 3H2O + 3CO2 + Na3C6H5O7
1 Alka Seltzer tablet has about1.92 grams of NaHCO3
1.92 grams of NaHCO3
produces how many mols of CO2?
5. Stoichiometry HWY
Steps to solve stoichiometry problems
1. Convert grams to mols- calculate molar mass- side ways T (how to setup?)
2. Use Mole Ratio
to move from this side of to this side
- how to setup?
5. Stoichiometry HWY
1. Br2 + 5F2 2BrF5a. 100 g of Br2. How many mols BrF5?b. 100 g of F2. How many mols of BrF5?
2. C5H12 C5H8 + 2H2a. 100 grams of C5H12. How many mols C5H8?b. 100 grams of C5H12. How many mols H2?
3. 2H2 + O2 2H2Oa. 100 grams of O2 can produce how many mols H2O?b.100 grams of H2 can produce how many mols H2O?
Solid lithium hydroxide, LiOH, is used in space
shuttles to remove exhaled carbon dioxide. The
reaction produces solid lithium carbonate, Li2CO3,
and liquid water, H2O.
2LiOH + CO2 Li2CO3 + H2O
How many grams H2O can be produced
by 1000 grams of LiOH?
Steps to solve stoichiometry problems
1. Convert grams to mols- calculate molar mass- side ways T (how to setup?)
2. Use Mole Ratio to move from this side of to this side
- how to setup?
3. Convert mols to grams- calculate molar mass- side ways T (how to setup?)
5. Stoichiometry HWY
2Na + Cl2 2NaCl
500 grams of Na will make how many molsof NaCl?
Write in complete sentences of how to solve this question
Then solve
5. Stoichiometry HWY
C6H12O6 2C2H5OH + 2CO2
1150 g of sugar, C6H12O6. ? Grams C2H5OH
C5H11OH + 15O2 CO2 + 12H2O88 grams C5H11OH, how many grams of CO2?
CH3NO2 + 3Cl2 CCl3NO2 + 3HCl500 grams CCl3NO2. How many grams
CH3NO2
Mg +O2 2MgO25.5 g Mg. ? Grams O2?
Summarize the article in TWO sentences.
What is the main point, or points, of the article?
What is your opinion regarding the main point of the article?
How is this article related to the Law of Conservation of Mass? Cite 2 examples as
evidence
IGNORE questions at end of article
5. Limiting Reactants
OBJECTIVE:
Running out of “ingredients”
5. Limiting Reactants
8 buns + 12 pattiesWhich will run out first?
Limiting Reactant Excess Reactant
▪ The reactant that controls the quantity of product that can form in a chemical reaction
▪ Stuff that runs out first
▪ The reactant that is not completely used up in a chemical reaction
▪ Stuff left over
5. Limiting Reactants
8 buns + 12 pattiesWhich is limiting?
5. Limiting Reactants
4 franks + 12 bunsWhich is limiting?
2H2 + O22H2O
– 10 grams of H2
– 10 grams of O2.
– How many moles of H2O?
How to Solve?
Identify limiting reactant.
Limiting Reactant = Smaller Number
5. Limiting Reactants
Fe + S Fe2S3
2Fe + 3S Fe2S3
–100 grams of Fe–100 grams of S –How many grams of Fe2S3? –(Identify limiting reactant)
5. Limiting Reactants
NO +Cl2NOCl–4 mol of NO–4 mol of Cl2
–How many mol of NOCl?
BALANCE FIRST!!
5. Limiting Reactants
NO +Cl2NOCl–100g of NO –100g of Cl2
–How many mol of NOCl?
5. Limiting Reactants
Fe + S Fe2S3
– 10 moles of Fe
– 12 moles of S.
– How many moles of Fe2S3? Identify limiting reactant.
– 150 g of Fe
– 120g of S.
– How many grams of Fe2S3?
▪ Go to Word Document
5. Limiting Reactants
H2 +N2NH3
–12L of H2
–10L of N2
–How many grams of NH3?
–25g of H2, 35g of N2. How many liters of NH3?
5. Limiting Reactants
6. Percentage Yield
OBJECTIVE:
Measuring Efficiency
6. Percentage Yield
Efficiency of a reaction =
Percentage Yield
Formula for Percentage Yield
6. Percentage Yield
Actual YieldTheoretical Yield
▪ What is actuallyproduced
▪ Always LESS THAN theoretical yield.
▪ What you have been calculating so far
2Al + 6HCl -> 2AlCl3 + 3H2
You calculated a theoretical yield of 8.77 grams for AlCl3.
But only 5.66 grams of AlCl3 is actually produced.
What is the percentage yield?
You start with 42 grams of Al.
The actual yield for H2 is 4.04.
What is the percentage yield for H2?
6. Percentage Yield
2Al + 6HCl -> 2AlCl3 + 3H2
The theoretical yield is 98.5 grams for AlCl3. This reaction has 77 percentage yield.
What is the actual yield?
2H2O2 -> 2H2O +O2
1. How many grams of O2 is produced from 250g of H2O2?
2. If reaction has 68% yield, how many grams of O2 is actually produced?
2P +Cl2 -> 2PCL3
500L (actual yield) of PCl3 needs to be produced. The reaction as a 75% yield.
How many grams of Cl2 is needed?
Hint: 1. Find theoretical yield of PCl3.
2. Then 3-step starting with 500L of PCl3 and finding grams of
Cl2
2P +Cl2 -> 2PCl3
PY for PCl3 = 72%
AY for PCl3 = 300 grams
How many Liters of Cl2 needed ?
3H2 + N2 -> 2NH3
1. 40 grams of H2 and 40 grams of N2. How many grams of NH3 can be produced?
2. Which reactant is limiting?
3. 36 grams of NH3 is actually produced. What is the percentage yield?
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