Unit 6. Chapter 10: The MOLE! Date In Class Homework. % Composition & Calculating Empirical Formulas

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Date In Class Homework

10/22 Thur Counting By Mass Lab

10/23 Fri (mole day!!!) THE MOLE! in room 137

10/26 Mon (LSM) More on the Mole Watch empirical and molecular formula video.

10/27 Tue % Composition & Calculating Empirical Formulas

work on problems in the packet (1-7 on page 8)

10/28 Wed. Nomenclature Review Prelab for Hydrated Crystal Lab

10/29 Thurs Hydrated Crystal Lab

10/30 Fri NO SCHOOL! whoo hoo!!! work on problems in the packet (8- 20 on pages 9)

11/2 Mon Work on Unit Packet Finish all problems in Unit Packet (21 – 28 on page 10-11) 11/3 Tues Review for Chapter 10 Test Study for Test

11/4 Wed Chapter 10 Test prelab for Types of Chemical Reactions

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Notes for chapter 10:

1. What is a mole?

2. What units can a mole be converted to/from: a.

b. c.

MOLE/PARTICLE (MOLECULES AND ATOMS) 3. How many molecules are in a mole?

4. When converting from molecules/atoms you _____________________________________ 5. When converting from moles to molecules/atoms you ______________________________ Mole/Particle Practice:

a. How many moles are in 5.3 x 10

26

atoms of copper?

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3 MOLE/MASS (GRAMS)

6. Define atomic mass in terms of moles:

a. What is the atomic mass of 1 mole of a hydrogen atom? b. What is the atomic mass of 1 mole of an aluminum atom? 7. Define molar mass.

8. Show how you calculate the molar mass of water (H2O)

9. When converting from grams to moles you _____________________________________ 10. When converting from moles to grams you _____________________________________ Mole/Gram Practice:

a. How many grams of Iron are in 2.7 moles of Iron?

b. How many moles of Zinc are in 15 grams of Zinc?

c. How many grams are in 23 moles of CO2?

d. How many moles are in 562 grams of CO2?

e. Calculate the molar mass of ammonium carbonate

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4 MOLE/VOLUME (LITERS)

11. What does STP stand for?

12. What is the temperature and pressure at STP?

13. At STP when converting from liters to moles you _____________________________________ 14. At STP when converting from moles to liters you _____________________________________ Mole/Liter Practice:

a. How many liters are present in 10 moles of H2 at STP?

b. How many moles are in 17 L of water vapor?

THE MOLE: A BRIGE BETWEEN PARTICLES, GRAMS, AND LITERS

15. List the steps used in calculating how many molecules of H2O are present in 10.8 grams?

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5 Video on Empirical and Molecular Formulas: Link: https://www.youtube.com/watch?v=wnRaBWvhYKY or search Tyler Dewitt Empirical and Molecular Formulas

Video title is: Empirical Formula and Molecular Formula Introduction

Guided Notes Questions

What is a molecular formula?

What is an empirical formula?

Use ethene (which is really butene….) as an example of a molecular and empirical formula.

Write the molecular formula and empirical formula for cyanuric triazide

What do you divide by to get the empirical formula for C5H10O5?

What is the empirical formula for C5H10O5?

When is the molecular formula the same as the empirical formula?

Why can many compounds have the same empirical formula? Show an example of several molecular formulas that come from the same empirical formula.

Check your learning Practice.

Write the empirical formulas for the following compounds: 1. H2O2

2. H2O

3. C2H10O4

4. C5H10O2

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6 Percent Composition and Calculating Empirical Formulas:

1. What is a percent composition?

2. Write the equation for calculating % composition? % composition = x100

3. Using the molar mass we calculated for ammonium carbonate from page 3 e, show how to calculate the percent of each element in the compound.

a. N

b. H

c. C

d. O

4. Calculate the percentage composition for all the elements in barium nitrate?

5. Write each step for how to calculate the empirical formula of a compound using mass or percent composition. a. Step 1.

b. Step 2.

c. Step 3.

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7 6. Use the steps in 5. to calculate the empirical formula of a compound that contains 28.4 g copper and 71.6 g

bromine?

7. Follow the steps in 5. to calculate the empirical formula of a compound that contains 36.4% Carbon and 63.6% Nitrogen

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Unit 6. Chapter 10: The MOLE! Name:____________________________________

8 Homework Practice Problems – answers on last pages

1. Find the molar mass (g/mole) of:

a. Na e. MgI2

b. C f. AgClO2

c. O2 g. Cu(NO3)2

d. KOH h. Mg3(PO4)2

2. Calculate the mass (grams) of:

a. 1.00 mole of CaCl2 b. 2.0 mol of Al

c. 0.50 mol H2SO4 d. 0.10 mole of Na2O

3. Calculate moles in:

a. 16.0 g of O2. b. 3.2 g of H2O

c. 168 g of NaHCO3 d. 6.25g Al2O3

4. Calculate the number of molecules in:

a. 3.0 moles OF ANYTHING b. 32 mol of CH4

c. 1.4 mol of NH3 d. 2.5 mol O2

5. Calculate the number of moles in:

a. 1.204 x 1024 molecules b. 3.5 x 1024 molecules of HCl

c. 6.5 x 1029 molecules of H2SO4 d. 3.5 x 10 12

molecules of SO3

6. Calculate the number of moles in:

a. 45 L F2 b. 3.5 L SO2

c. 78.9 L CO

7. Calculate the volume in liters of:

a. 4.50 mol NO2 b. 8.5 mol CO2

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9 8. Determine mass in grams of 40.0 moles of sodium carbonate.

9. How many grams are in 0.020 moles of Sn

10. How many liters are in 6.0 mol O2

11. Calculate moles in 510.0 g of aluminum sulfate.

12. How many moles are in 40.0 g Na2CO3

13. How many moles are in 3.00 L of N2

Moles are the Bridge between units:

14. Determine the mass in grams of 2.35 molecules of C12H22O11

15. How many liters are present in 100g of CO2 (at STP)?

16. How many sulfur atoms are present in 25.0 grams of H 2SO4?

17. How many atoms are in 2.00 grams of carbon? (2 steps)

18. Determine the mass of 50L of CO.

19.(challenge) How many moles of carbon atoms are in 3.00 grams of C2H5OH?

Percent Composition:

20. Determine the percentage composition of each element in the following compounds: a. magnesium iodide, MgI2

%Mg = _________ % I = _________

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Empirical vs. Molecular formulas

21. Write the empirical formula for each of the following compounds. (Not all will need to be changed!) a. Na2O2 ____________________ d. Cu2C2O4 ____________________

b. Li2SO4 ____________________ e. CaC4H4O6 ____________________ c. Hg2F2 ____________________ f. C6H6 ____________________ Calculating Empirical Formulas

22. What is the empirical formula of a compound that contains 1.67 g of Ce and 4.54 g of I?

23. What is the empirical formula of benzoic acid (a food preservative) if it contains 68.8% carbon, 4.95% H, and 26.2% O by mass?

24. Calculate the empirical formula for a compound made up of 63.6% iron and 36.4% sulfur.

25. Calculate the empirical formula of a hydrate that is 48.8% magnesium sulfate and 51.2% water (from lab)

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Nomenclature Practice:

27. Provide the name for each of the following:

a. PbCl2 g. H2CO3 b. Hg(NO3)2 h. Sn3(PO4)2 c. AgF i. N3Br7 d. Ca(OH)2 j. H2SO3 e. HF k. HNO3 f. S4O6 l. Cu(C2H3O2)2

28. Provide the formula for each of the following:

a. Iron (III) oxide g. acetic acid b. aluminum iodide h. carbon monosulfide c. Lead (II) sulfate i. phosphoric acid d. mercury (II) nitrate j. chlorous acid e. tin (IV) hydroxide k. hydroselenic acid f. ammonium sulfide l. disulfur noniodide

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12 Chemistry – Chap. 10 HW- Answers

1. a. 22.99 g b. 12.01 g c. 32.00 g d. 56.11 g

e. 278.11 g f. 175.32 g g. 187.56 g h. 262.87 g 2. a. 110.98 g b. 53.96 g c. 49 g d. 6.2 g 3. a. .500 mol b. .18 mol c. 2.00 mol d. .0613 mol 4. a. 1.8 x 1024 molecules b. 1.9 x 1025 molecules c. 8.4 x 1023 molecules

d. 1.5 x 1024 molecules

5. a. 2.000 mol b. 5.8 mol c. 1.1 x 106 mol d. 5.8 x 10-12 mol 6. a. 2.0 mol b. .17 mol c. 3.52 mol

7. a. 101 L b. 190 L c. 2350 L

8. 40.0 moles Na2CO3 x 106g/1mol = 4240g

9. 2.4 g 10. 134 L

11. 510.0 g aluminum sulfate x 1molH2SO4/342g = 1.5 mol

12. 0.377 mol 13. 0.139 mol

14. 2.35 molecules C12H22O11  6.02 x 1023 molecules x 342g/mol = 1.34 x 10-21g

15. 100g CO2  44g x 22.4L/mol = 50.9 L

16. 1.5 x 1023 _{atoms S}

17. 2.00 grams C  12 gC x 6.02 x 1023 _{atoms/mol = 1.0 x 10}23_{atoms C} 18. 50L of CO  22.4L x 28g/mol = 62.5 g CO

19. 3.00 grams C2H5OH  46g x 2C/1 C2H5OH = 0.13 mol C atoms

20. a. %Mg= 24.3 / 278.3 x 100 = 8.7% %I = 254/278.3 x 100 = 91.3% b. Cl = 71/207 x 100 = 34.3% O = 96 / 207 x 100 =46.4%

21. Write the empirical formula for each of the following compounds. (Not all will need to be changed!) a. Na2O2 _NaO_______________ d. Cu2C2O4 ___CuCO2

b. Li2SO4 _ Li2SO4 e. CaC4H4O6 __ CaC4H4O6

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13 22. What is the empirical formula of a compound that contains 1.67 g of Ce and 4.54 g of I?

1.67g/140= 0.012mol 0.012/0.012 = 1

4.54g/127 = 0.036 mol 0.036/0.012 = 3 CeF3

23. What is the empirical formula of benzoic acid (a food preservative) if it contains 68.8% carbon, 4.95% H, and 26.2% O by mass?

68.8g C/12 = 5.73 mol C 5.73/1.64 = 3.5 x 2 7.0 4.95g H/1 = 4.95 mol H 4.95/1.64 = 3 x 2 6

26.2 g O / 16 = 1.64 mol O 1.64/1.64 = 1 x 2 2 C7H6O2

24. Calculate the empirical formula for a compound made up of 63.6% iron and 36.4% sulfur.

63.6/55.8 = 1.14 FeS

36.4g/32 = 1.14

25. Calculate the empirical formula of a hydrate that is 48.8% magnesium sulfate and 51.2% water 48.8g/120 = 0.405 mol MgSO4 0.405/0.405 = 1

51.2 g/18 = 2.84 mol H2O 2.84/0.045 = 7 MgSO4 7 H2O

26. Calculate the formula for a hydrate that is 37.07% sodium carbonate and 62.93% water 37.07g/106 = 0.356 mole (Na)2CO3 0.356/0.356 1

62.9g / 18 = 3.49 mol H2O 3.49 / 0.356 9.8 Na2CO3 * 10 H2O

27. Provide the name for each of the following:

a. Lead (II) chloride b. mercury (II) oxide c. silver fluoride d. calcium hydroxide e. hydrofluoric acid f. tetrasulfur hexoxide g. carbonic acid h. tin(II) phosphate i. trinitrogen heptabromide j. sulfurous acid k. nitric acid l. copper (II) acetate 28. Provide the formula for each of the following:

a. Fe2O3 g. HC₂H₃O₂ b. Al I3 h. CS c. PbSO4 i. H3PO4 d. Hg(NO3)2 j. HClO2 e. Sn(OH)4 k. H2Se f. (NH4)2S l. S2I9