Name:___________________________
Period:__________________________
Chemistry Unit 11 – Moles
Objective
10.1 Describe the mole and
representative particle
relationship using Avogadro’s
number.
10.2 Identify the relationship
between moles and GAM,
GFM, and GMM.
Learning Opportunities
□
□
□
Read p. 286-296.
Podcast 6.1 Measuring Amounts of
Substances
Answer 3-4 pg. 291, 5-6 pg. 292, 9-14 pg. 296
Compounds Review Practice Sheet
The Mole and Avogadro’s Number
Read p. 293- 299.
Podcast 6.2A Molar Mass
Answer 7,8,15 pg. 296; 16 and 17, p. 298; 1819 pg. 299; 24, 26, 27 pg. 303
Gram Formula Mass
Moles Mini Lab
Podcast 6.2B Moles Mini Lab (Watch
AFTER Completing the Lab)
Moles and Mass
Read p. 300-303.
Podcast 6.3 Molar Volume
Answer 20-21 pg. 301, 22-23 pg. 302, 25,
28-31 pg. 303,
Calculations with Moles Group Assignment
Mixed Mole Problems
Chapter 10 Quiz
Read p. 305-308.
Podcast 6.4 Percent Composition
Answer 32-33, p. 306; 34-35, p. 307; 43 and
44, p. 312
Read p. 309-313.
Podcast 6.5 Empirical Formula and
Molecular Formula
Answer 36 and 37, p. 310; 38 and 39, p. 312,
45 and 46, p. 312
Digenite Lab (Empirical Formula of
Copper (?) Sulfide)
Unit 9 Review
□
Unit 10 Test
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□
□
□
10.3 Describe STP and the
relationship between volume of
a gas and moles.
10.4 Determine percent
composition by mass
10.5 Identify molar ratios to
determine empirical and
molecular formulas
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□
□
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Unit 10 Test
Suggested
Due Date
03/02
Date
Completed
03/03
03/05
03/06
03/10
03/1103/12
1
Assignment Write the corresponding name or formula for each of the following:
1. lead (II) sulfide
16.H2CrO4
31. nitrogen trichloride
2. perchloric acid
17. Al2O3
32.
3. hydrogen fluoride
18.
33. potassium hydrogen
4. zinc hydroxide
19.H2SO3
5. hydrobromic acid
20.
6. SF6 (l)
21. iron (II) nitride
7. HNO2 (aq)
22. tetraphosphorus
8. HCl (g)
N2O3
HgO (aq)
decoxide
plumbic carbonate
sulfite
34.
boric acid
35.
barium sulfite
36.
SnCl2
37.
CaHPO3 (s)
23.
copper (I) oxide
38.
H2S (g)
24.
hypochlorous acid
39.
Li2O2
11. ammonium carbonate
25.
potassium peroxide
40.
Mn(NO2)2
12. chromium (III) sulfite
26.
CuSO3
41.mercuric phosphate
13. nickel (II) sulfate
27.
CO
42. sodium hydrogen
28.
MgS
9. PbCl2
10.
ZnSO4
hexahydrate
14.hydrosulfuric acid
carbonate
43. copper (I) hydrogen
29.
KClO2
sulfate
15. sulfur trioxide
30.
HI (aq)
2
44.
carbon
46.
SO2 (aq)
49.
P2O3
tetrachloride
47.
MgSO49H2O
50.
H3PO3
48.
HC2H3O2
45. ammonium phosphate
Podcast 6.1: Measuring the Amount of Substance
The Mole
Measuring the Amount of “Stuff”
 Suppose you needed to measure the amount of sand in
a child’s sandbox…
 You could count each grain of sand (the number of
______________________)
 You could weigh the sand (_________________)
 You could measure how many bucketfulls of sand there
are (_______________________)
 You could use _________________ to convert the number of particles to mass or to volume
and vice versa
It’s kinda like… Cooking!(only we don’t lick the spoon)
1 Mole = ______________________________ particles
Defining particles…
Elements have particles called ______________________
Compounds have particles called _______________________
Moles are like measuring cups
Mollionaire
Q: how long would it take to spend a mole of $1 coins if they were being spent at a rate of 1 billion
per second?
A:
Comparing sugar (C12H22O11) & H2O
Same
Volume?
1 gram each
1 mole each
Mass?
3
# of Moles?
# of Molecules?
# of Atoms?
4
Converting Moles to Particles
Example: How many moles of magnesium is 1.25 x 1023 atoms of magnesium?
Practice Problems
1. What is Avogadro’s Number?
2. How many moles of sodium is 6.482 x 1023 atoms of sodium?
3. If there are 1.03 x 105 mol cesium, then how many atoms are there?
4. If there are 8.925 x 10-3 mol of sulfur, then how many atoms are there?
5. How many atoms are in 2.12 mol of propane (C3H8)?
6. You have 1.75 mol Ba3(PO4)2
a)What is the name of this compound.
b) How many atoms are there?
7. a) How many moles are there in 1.50 x 1023 molecules of NH3
b)What is the name of this compound?
5
THE MOLE AND AVOGADRO’S NUMBER
One mole of a substance contains Avogadro’s Number (6.02 x 1023 ) of molecules.
How many molecules are in the quantities below?
1. 2.0 moles
______________________________
2. 1.5 moles
______________________________
3. 0.74 moles
______________________________
4. 15 moles
______________________________
5. 0.36 mole
______________________________
How many moles are in the number of molecules below?
1. 6.02 x 1023
______________________________
2. 1.204 x 1023
______________________________
3. 1.5 x 10
20
4. 3.4 x 10
26
______________________________
______________________________
5. 7.5 x 1019
______________________________
6
Podcast 6.2: Molar Mass
Molar Mass – Use the Periodic Table
• The mass of one mole is called “molar mass”
• Example: 1 mol Li = ______________
• This is expressed as ______________
Examples
What are the following molar masses?
S
SO2
Cu3(BO3)2
Calculate molar masses (to 2 decimal places)
1. CaCl2
2.
(NH4)2CO3
3.
O2
4.
Pb3(PO4)2
5.
C6H12O6
Molar Mass – Don’t be fooled by other names!
• Gram Atomic Mass (GAM) – molar mass of an _________________________________
(all atoms are identical)
• Gram Molecular Mass (GMM) – molar mass of a
__________________________________________ (atoms that are covalently bonded)
• Gram Formula Mass (GFM) molar mass of an
_____________________________________________ (ions bound in specific simple mole
ratios)
Converting between Grams and Moles
• If we are given the # of grams of a compound we can determine the # of moles, & vise-versa
• In order to convert from one to the other you must first calculate molar mass
• Use a t-table to decide which conversion factor to use.
Formula
Molar Mass
(g/mol)
Mass
(g)
HCl
H2SO4
0.25
53.15
NaCl
Cu
Moles
(mol)
3.55
1.27
7
Mole Mass Practice Problems
1. How many moles are represented by 16.0 g of ethanol, C2H5OH?
2. How many grams of glucose are in 6.63 x 1023 molecules of glucose, C6H12O6?
3. How many moles of methanol, CH3OH, are in 6.53 x 1023 molecules of methanol?
4. How many moles of sodium chloride are in 16.0 g of sodium chloride?
5. How many molecules of potassium hydroxide are in 40.6 g?
6. How many grams of chromic chloride are in 7.14 moles of chromic chloride?
8
GRAM FORMULA MASS
Determine the gram formula mass (the mass of one mole) of each compound below.
1. KMnO4
______________________________
2. KCl
______________________________
3. Na2SO4
______________________________
4. Ca(NO3)2
______________________________
5. Al2SO4)3
______________________________
6. (NH4)3PO4
______________________________
7. CuSO45 H2O
______________________________
8. Mg3(PO4)2
______________________________
9. Zn(C2H3O2)2 2 H2O
______________________________
10. Zn3(PO4)2 4 H2O
______________________________
11. H2CO3
______________________________
12. Hg2Cr2O7
______________________________
13. Ba(ClO3)2
______________________________
14. Fe2(SO3)3
______________________________
15. NH4C2H3O2
______________________________
9
MOLES AND MASS
Determine the number of moles in each of the quantities below
1. 25 g of NaCl
______________________________
2. 125 g of H2SO4
______________________________
3. 100. G of KMnO4
______________________________
4. 74 g of KCl
______________________________
5. 35 g of CuSO4 5 H2O
______________________________
Determine the number of grams in each of the quantities below
1. 2.5 moles of NaCl
______________________________
2. 0.50 moles of H2SO4
______________________________
3. 1.70 moles of KMnO4
______________________________
4. 0.25 moles of KCl
______________________________
5. 3.2 moles of CuSO4 5 H2O
______________________________
10
The Mole Lab
Purpose: To determine how the number of moles or particles for a specific substance can be determined
using Avogadro’s Number and the mass of a substance on the periodic table.
Hypothesis:
_____________________________________________________________________________
_____________________________________________________________________________
_____________________________________________________________________________
Materials: (Indicate only those that you used)
_____________________________________________________________________________
_____________________________________________________________________________
_____________________________________________________________________________
Procedure: (If a calculation is required, then you must show your work in your data analysis!)
1. Obtain a Mass measurement for a piece of copper Wire and record it in your data table.
2. Calculate the number of moles in your piece of wire. (Remember that Copper’s Symbol is Cu and all
calculations should be shown in data analysis.)
3. Calculate the total number of Copper of atoms that exist in your wire.
4. Gather approximately 1.4 g of Calcium or Aluminum on a watch glass. Record the actual amount of mass
that you collected in your data table.
5. Calculate the # of moles of Calcium or Aluminum that you collected.
6. Calculate the # of atoms of Calcium or Aluminum that you collected.
7. Calculate the # of moles and atoms that you should have collected.
8. Calculate your Percent Error for the # moles of Calcium or Aluminum that you collected.
9. Obtain 1.4 g of sodium carbonate.
10. Calculate the # of moles of the sample you collected.
11. Calculate the # of formula units of the sample you collected.
12. Calculate the # of atoms for your sample.
13. Calculate your Percent Error for the # moles of sodium carbonate.
Data:
Substance
Symbol or
Formula
Mass (g)
# of Moles
(mol)
Molecules
Atoms
Copper
Sodium
Carbonate
Data Analysis:
Copper Calculations:
Percent Error Calculation:
Help with Calculations
____________________________________________________________________________________
11
Calcium or Aluminum Calculations:
Percent Error Calculation:
____________________________________________________________________________________
Sodium Carbonate Calculations:
Percent Error Calculation:
____________________________________________________________________________________
Conclusion:
12
Podcast 6.3: Volume of a Mole of Gas
•
Volume varies with a change in temperature of pressure
•
The volume of a gas is usually measured at Standard Temperature and Pressure, _________
•
Standard Temperature: _______oC
•
Standard Pressure: _________ kPa or 1 atm
Volume at STP
•
At STP, 1 mole of any gas fills ___________ L(molar volume of a gas)
•
22.4 L of a gas at STP has ____________ particles
Molar Density
•
Density =
•
Molar Density will always have the same t-table except for the first square
Mixed Mole Problems
A. How many grams are there in 1.5 x1025 molecules of CO2?
B. What volume would the same CO2 occupy at STP?
C. What is the molar density of CO2 at STP?
13
14
The Mole and Volume
For gases at STP (273 K and 1 atm pressure), one mole occupies a volume of 22.4 L.
What volume will the following quantities of gases occupy at STP?
1. 1.00 mol of H2
______________________________
2. 3.20 moles of O2
______________________________
3. 0.750 mole of N2
______________________________
4. 1.75 moles of CO2
______________________________
5. 0.50 mole of NH3
______________________________
6. 5.0 g of H2
______________________________
7. 100. g of O2
______________________________
8. 28.0 g of N2
______________________________
9. 60. g of CO2
______________________________
10. 10. g of NH3
______________________________
15
MIXED MOLE PROBLEMS
Solve the following problems.
1. How many grams are there in 1.5 x 1025 molecules of CO2?
______________________________
2. What volume would the CO2 in Problem 1 occupy at STP?
______________________________
3. A sample of NH3 gas occupies 75.0 liters at STP. How many molecules is this?
______________________________
4. What is the mass of the sample of NH3 in Problem 3?
______________________________
5. How many atoms are there in 1.3 x 1022 molecules of NO2?
______________________________
6. A 5.0 g sample of O2 is in a container at STP. What volume is the container?
______________________________
7. How many molecules of O2 are in the container in Problem 6? How many atoms of oxygen?
______________________________
______________________________
16
Podcast 6.4 Percent Composition
•
Percent Composition: The relative amounts of each
_____________________________________ in a compound expressed as a percent
• Also called “percent by mass”
• % means “part over whole”
Example 1
8.2 g of Magnesium reacts completely with 5.40 g of Oxygen to form a compound. What is the
percent composition of each element in the compound?
If all you are given is the formula or name of a compound, then you must use Molar Mass from the
Periodic Table
• Example: Calculate the % composition of propane, C3H8.
Percent Composition can also be used as a conversion to solve for mass.
• Calculate the mass of carbon in 82.0 g of propane C3H8
17
PERCENTAGE COMPOSITION
Determine the percentage composition of each of the compound below.
1. KMnO4
K=
______________________________
Mn = ______________________________
O=
______________________________
2. HCl
H=
______________________________
Cl =
______________________________
3. Mg(NO3)2
Mg = ______________________________
N=
______________________________
O=
______________________________
4. (NH4)3PO4
N = ______________________________
H = ______________________________
P = ______________________________
O = ______________________________
5. Al2(SO4)3
Al = ______________________________
S = ______________________________
O = ______________________________
Solve the following problems.
6. How many grams of oxygen can be produced from the decomposition of 100. g of
KClO3?
_______________________
7. How much iron can be recovered from 25.0 g of Fe2O3? ______________________
8. How much silver can be produced from 125 g of Ag2S? _______________________
18
DETERMINING EMPIRICAL FORMULAS
What is the empirical formula (lowest whole number ratio) of the compounds below?
1. 75% carbon, 25% hydrogen
______________________________
2. 52.7% potassium, 46.3 % chlorine
______________________________
3. 32.1 % aluminum, 25.4 % phosphorus, 52.5 % oxygen
______________________________
4. 13% magnesium, 87% bromine
______________________________
5. 32.4% sodium, 22.5 % sulfur, 45.1 % oxygen
______________________________
6. 25.3 % copper, 12.9 % sulfur, 25.7 % oxygen, 36.1 % water
______________________________
19
DETERMINING MOLECULAR FORMULAS (TRUE FORMULAS)
Solve the problems below.
1. The empirical formula of a compound is NO2. Its molecular mass is 92 g/mol. What is its molecular
formula?
______________________________
2. The empirical formula of a compound is CH2. Its molecular mass is 70 g/mol. What is its molecular
formula?
______________________________
3. A compound is found to be 40.0% carbon, 6.7 % hydrogen, and 53.5% oxygen. Its molecular mass
is 60. g/mol. What is its molecular formula?
______________________________
4. A compound is 64.9% carbon, 13.5 % hydrogen, and 21.6% oxygen. Its molecular mass is 74 g/mol.
What is its molecular formula?
______________________________
5. A compound is 54.5% carbon, 9.1% hydrogen, and 36.4% oxygen. Its molecular mass is 88 g/mol.
What is its molecular formula?
______________________________
20
Copper Sulfide Lab
Overview: In this experiment you will determine the mass of sulfur that will combine
with a given amount of copper under the experimental conditions used in the laboratory.
From this data, the empirical formula can be calculated for copper (?) sulfide.
Materials: Bunsen burner, crucibles, tongs, clay triangle, sulfur, copper wire, scale, ring
stand, ring clamp, and heat gloves.
Procedure:
1. Place a clean crucible on a clay triangle and heat to redness (at station). Allow the
crucible to cool to room temperature and weigh to the nearest 0.01 g without the
cover. Record this data in your data table.
2. While the crucible is cooling, obtain a 2 inch sample of copper wire and coil it.
3. After weighing the crucible, place the coiled wire into the crucible. Weigh the
crucible with the copper wire to the nearest 0.01 g. Add about 3 grams of sulfur to
the crucible and weigh the crucible (copper + sulfur) to the nearest 0.01 g.
4. Cover the crucible and place it on the clay triangle located in the hood. Gently heat
for about four minutes . Gradually increase the heat until the bottom of the
crucible becomes red hot; also heat the sides and the cover by moving the Bunsen
burner around the crucible. Continue heating until the sulfur stops burning
around the crucible rim.
5. Allow the crucible to cool, remove the cover with tongs, and examine contents for
traces of excess sulfur. If there is still sulfur in the crucible continue heating until
traces are gone.
6. Cool the crucible to room temperature. Weigh the crucible and its contents to the
nearest 0.01 g. Record your data.
Prelab Questions
1. A compound is formed when 9.03 g Mg combines completely with 3.48 g N. What is
the percent composition of this compound?
2. When a 14.2 g sample of mercury (II) oxide is decomposed into its elements by
heating, 13.2 g Hg is obtained. What is the percent composition of the compound?
3. Calculate the percent composition of these compounds:
a. ethane, C2H6
b. sodium hydrogen sulfate
c. ammonium nitrate
4. Calculate the empirical formula of each compound.
a. 94.1% O, 5.9% H
b. 67.6% Hg, 10.8% S, 21.6% O
5. 1,6-diaminohexane is used to make nylon. What is the empirical formula of this
compound if it is 62.1% C, 13.8% H, and 24.1% N?
6. Find the molecular formula of ethylene glycol, which is used as antifreeze. The
molar mass is 62 g/mol and the empirical formula is CH3O.
21
Data Table:
Mass (g )
Trial #1
Trial #2
Trial #3
Trial #4
Crucible
Crucible +
Copper
Copper
Crucible +
Product
Product
Copper Sulfide
= Copper +
Sulfur
Sulfur
Mass of Copper = Mass of Crucible & Copper – Crucible
Mass of Product = Mass of Crucible & Product – Crucible
Mass of Sulfur = Mass of Product – Copper
Data Analysis :
In the Data Analysis the empirical formula for each trial needs to be calculated
based on the amount of grams obtained of copper and sulfur.
Questions:
1. A sample of iron oxide is found to contain 0.0286 moles of iron and 0.0429 moles
of oxygen.
a. What is the empirical formula for iron oxide?
b. Based on the questions above is compound Ferric Oxide or Ferrous Oxide?
Explain.
2. Based on your empirical formulas, is the compound more likely Cupric Sulfide or
Cuprous Sulfide? Explain.
22
Digenite Lab Report Rubric
Table of Contents
Includes the title, page numbers, and date of experiment
Point
s
Earne
d
Point
s
Possi
ble
2
Title
Capitalized appropriately, relates to the experiments, NOT
underlined, but rather just centered at the top of the lab report
1
Problem Statement
- Independent variable, dependent variables, constants (at
least 3), and the control are stated
- Purpose and Problem are testable and clearly stated
5
2
Hypothesis
States what you are doing, what you predict will happen, and
why you think that will happen. If…Then…Because
3
Materials
A list of all materials used in the experiment
1
Procedure
Write a complete, DETAILED procedure.
Data
Organized table that shows the data you have collected during
the experiment
- Include an appropriate title
- Clearly organize and label data columns and rows
- Units are clearly identified
- Accuracy of data is appropriate to measuring equipment or
instruments
- Data from multiple trials is clearly shown
- Data and table lines are neat and presentable (USE A RULER)
Prelab Questions
Show your work for each calculation. Get your teacher’s stamp on
your prelab BEFORE you collect any data
Calculations
Part One: Determine the number of moles of both copper and sulfur
involved in the reaction (convert mass to moles)
Part Two: Find the simplest whole number ratio and write the
empirical formula
3
3
30
6
3
23
Part Three: Use statistical measures to compare class data and draw
conclusions (average, % Error compared to Digenite)
Questions:
Show Your Work!
4
1. A sample of iron oxide is found to contain 0.0286 moles of iron and
0.0429 moles of oxygen.
a. What is the empirical formula for iron oxide?
b. Based on the questions above is compound Ferric Oxide or
Ferrous Oxide? Explain.
2. Based on your empirical formulas, is the compound more likely
Cupric Sulfide or Cuprous Sulfide? Explain.
7
Conclusion
Written in paragraph form (minimum of 3 paragraphs)
1
Support or refute your hypothesis. Give reasons why. USE YOUR
DATA!
Discuss any EXPERIMENTAL error you may have had in the
experiment. Remember, mistakes are not the same thing as
personal
error!
4
Discuss how to change the design to fix the errors. What further
questions or investigations does this lead to?
4
Discussion/Reflection
Discuss what you learned from this experiment and how it relates
to what we are learning in class and applications in the real world
(your world). Examples: Medicine, Pharmacy, Industry, Technology,
Mining
Prelab BONUS
Total Points
GRADE
5
4
up to
5
90
24
Unit 11 Test Review
General Topics
1. What is the SI unit for the amount of a substance?
2. What is Avogadro’s number?
3. What are the values for STP and what does it stand for?
P = _____________________
T = ______________________
4. What two things are needed to find a molecular formula?
5. What are the 4 steps needed to calculate an empirical formula?
10.1 The Mole: A Measurement of Matter (p. 286 – 299)
6. What is the molar mass of sucrose, C12H22O11?
7. What is the molar mass of each of the following compounds?
a. Phosphorus pentachloride (PCl5)
b. Uranium hexafluoride (UF6)
8. Calculate the molar mass of each of the following ionic compounds:
a. KMnO4
b. Ca3(PO4)2
9. How many moles is 3.52 x 1024 molecules of water?
10. How many atoms of zinc are in 0.60 mol of zinc?
11. What is the mass of 1.00 mol of oxygen (O2)?
10.2 Mole-Mass and Mole-Volume Relationships
12. What is the molar mass of each of the following compounds?
a. C6H12O6
b. NaHCO3
c. C7H12
13. Calculate the mass in grams of each of the following:
a. 8.0 mol lead (II) oxide, PbO
b. 0.75 mol hydrogen sulfide, H2S
d. KNH4SO4
d. 1.50 x 10-2 mol molecular oxygen, O2
e. 2.30 mol ethylene glycol, C2H6O2
c. 0.00100 mol silicon tetrahydride, SiH4
14. How many grams are in 1.73 mol of dinitrogen pentoxide, N2O5?
15. How many grams are in 0.658 mol of calcium phosphate, Ca3(PO4)2?
16. Calculate the number of moles in each of the following
a. 0.50 g sodium bromide, NaBr
b. 13.5 g magnesium nitrate, Mg(NO3)2
c. 1.02 g magnesium chloride, MgCl2
d. 0.00100 g monochloromethane, CH3Cl
e. 1.50 x 10-3 g propylene glycol,
C3H6(OH)2
25
17. A chemist plans to use 435.0 grams of ammonium nitrate, NH4NO3 in a reaction. How many moles
of the compound is this?
18. A solution is to be prepared in a laboratory. The solution requires 0.0455 mol of quinine,
C20H24N2O2. What mass, in grams, should the laboratory technician obtain in order to make the
solution?
19. What is the volume at STP of 2.66 mol of methane, CH4 gas?
20. How many moles is 135 L of ammonia, NH3, gas at STP?
10.3 Percent Composition and Chemical Formulas
21. A sample of a compound analyzed in a chemistry laboratory consists of 5.34 g of carbon, 0.42 g of
hydrogen, and 47.08 g of chlorine. What is the percent composition of this compound?
22. Find the percent composition of a compound containing tin and chlorine if 18.35 g of the compound
contains 5.74 g of tin.
23. If 3.907 g of carbon combines completely with 0.874 g of hydrogen to form a compound, what is the
percent composition of the compound?
24. From the formula for calcium ethanoate, Ca(C2H3O2)2 , calculate the mass of carbon that can be
obtained from 65.3 g of the compound.
25. How many grams of aluminum are in 25.0 g of aluminum oxide, Al2O3?
26. How many grams of iron are in 21.5 g of iron (III) oxide, Fe2O3?
27. Determine the empirical formula of each of the following compounds from the percent composition:
a. 7.8% carbon and 92.2% chlorine
b. 10.0% carbon, 0.80 % hydrogen,
and 89.1% chlorine
26
Practice Problems
28. Write the chemical formula for potassium hydroxide.
Determine the molar mass of potassium hydroxide.
Find the percent composition of potassium in potassium hydroxide.
29. What is the density of CO2 gas in g/L at STP?
30. How many moles is 4.67 x 1024 atoms of silicon?
31. How many atoms are in 2.75 mol CHCl3?
32. How many liters are there in 1100 g of CO2 at STP?
33. You find that 7.36 g of a compound has decomposed to give 6.93 g of oxygen. The only other
element in the compound is hydrogen. What is the percent composition?
34. Determine the empirical and molecular formula for a compound that contains 50.7% C, 4.2% H,
and 45.1% O. The molar mass of this compound is 142 g.
27