Molar Mass of Compounds - Edl. Molar Mass of Compounds Summary & Review 1. What does the subscript...

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?


OBJECTIVE:

Calculating molar mass of

compounds like NaCl, H2O,

Mg(OH)2


Where do you find the molar

mass of each element?


Get the molar mass of CO

C: 1

O: 1

x 12 = 12

x 16 = 16


Get the molar mass of CO2

2 = SUBscript

tells us how many

C: 1

O: 2

x 12 = 12

x 16 = 32


Get the molar mass of Ca3P2

Ca: 3

P: 2

x 40 = 120

x 31 = 62


Get the molar mass of H2O

H: 2

O: 1

x 1 = 2

x 16 = 16


Get the molar mass of Ca3(PO4)2

Ca: 3

P: 2

O:8

x 40 = 120

x 31 = 62

x 16 = 128


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?


OBJECTIVE: converting

grams to moles


a DOZEN of _____ = 12

a MOLE of something is equal to

602000000000000000000000or

6.02 x 1023

Avogadro’s Number


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


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



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



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


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


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


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


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


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


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


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


OBJECTIVE:Writing chemistry

equations like a recipe


H2 + O2 H2O

reactants “equals” productsyields

produces

3. Reactions

Show chemical changes with equations

Reactants Products

means “produces”


H2 + O2 H2O

subscripts = # of atoms


COEFFICIENTS

2H2 + O2 2H2O

coefficients = how many MOLES


2H2 + O2 2H2O

subscripts = # of atomscoefficients = how many


2H2 + O2 2H2O

Law of Conservation of MassNeed same number of atoms on

both sides of


“BALANCE” the reaction by adding COEFFICIENTS

H2 + O2 H2O2H2 + O2 2H2O


NEVERbalance by adding subscripts

2H2 + O2 2H2O

H2 + O2 H2O2


frame + wheels + chain + handlebars + pedals 1 bicycle

1 frame + 2 wheels + 1 chain + 1 handlebar + 2 pedals 1bicycle

What are those numbers?

COEFFICIENTS


2H2 + O2 2H2O

NEVER change subscripts


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



2. H3PO4 + Mg(OH) 2 Mg3 (PO4)2 + H2O

3. Al(OH)3 + H2SO4 Al2(SO4)3 + H2O


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


5. Al(OH)3 + H2SO4 Al2(SO4)3 + H2O


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



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



You start this reaction with 10 mols of KI. How many mols

of PbI2 is produced?

solve by using sideways t

4. Mole Ratio



You start this reaction with 10 mols of Pb(NO3)2. How many mols of PbI2 is produced?


4. Mole Ratio



You need to produce 10 molsof KNO3. How many mols of

Pb(NO3)2 do you need?


2H2 + O2 2H2O

You have 3 moles of O2

How many moles of H2O can you produce?

You have 3 moles of H2


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 do you solve something like this?

1. Calculate Molar Mass2. Grams Mol3. Mole Ratio

5. Stoichiometry HWY

OBJECTIVE:Molar Mass + Mole Ratio


What are we doing?Using reactions like recipies



H2 + O2 H2O

reactants “equals” products

Reactants Products

means “produces”


frame + wheels + chain + handlebars + pedals 1 bicycle

1 frame + 2 wheels + 1 chain + 1 handlebar + 2 pedals 1bicycle

What are those numbers?

COEFFICIENTS


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?


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?


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?)


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


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”


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


8 buns + 12 pattiesWhich is limiting?


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


Fe + S Fe2S3

2Fe + 3S Fe2S3

–100 grams of Fe–100 grams of S –How many grams of Fe2S3? –(Identify limiting reactant)


NO +Cl2NOCl–4 mol of NO–4 mol of Cl2

–How many mol of NOCl?

BALANCE FIRST!!


NO +Cl2NOCl–100g of NO –100g of Cl2

–How many mol of NOCl?


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


H2 +N2NH3

–12L of H2

–10L of N2

–How many grams of NH3?

–25g of H2, 35g of N2. How many liters of NH3?


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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