Chemistry
Unit 09 Chemical Quantities
Packet Grade: _______/_______
Unit 9: Chemical Quantities
WS: 10pts each
SWS: 20pts each
Reading: 30pts
Authors:
J. Galinski, S. Michalek, S. Menezes
Introductory Resources:
Addison-Wesley v.4 - Chapter 6
Main Idea Summary:
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The SI unit that measures the amount of substance is the mole.
A mole of any substance is composed of Avogadro’s number (6.02 × 10 23) of representative
particles.
The representative particle of most elements is the atom. A molecule is the representative
particle of diatomic elements and molecular compounds. The representative particle of ionic
compounds is a formula unit.
The molar mass of a substance is the mass in grams of one mole of that substance. One mole
of any substance contains the same number of representative particles as one mole of any
other substance.
Multiplying the number of moles of a substance by its molar mass gives the mass of the
substance.
One mole of any gas at STP occupies 22.4 L of volume.
The percent composition is the percent by mass of each element in a compound.
The percent by mass of any element in a given compound is calculated by dividing the
element’s mass by the mass of the compound and multiplying by 100%.
An empirical formula is the simplest whole number ratio of atoms of the elements in a
compound.
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Reading Comprehension Sheet
NAME: ______________________
6.1 Measuring Matter
What is the basic SI unit for measuring the amount of substance?
What is the mass of 90 average-size apples? Show the conversion.
6.2 The Mole
Mole
Avogadro’s Number
Representative particle
Diatomic Molecule
What mass of water in all the oceans of the Earth put together would equal the mass of 6.02 x 10 23 animal-moles?
6.3 The Gram Formula Mass
Gram Atomic Mass
Gram Molecular Mass
Gram Formula Mass
How many atoms are contained inn the gram atomic mass of an element?
What is mole defined in this section as?
6.4 The Molar Mass of a Substance
Molar mass
What is the difference between gam, gmm, and gfm in comparison to molar mass?
6.5 Mole—Mass Conversion
How do you convert from grams to moles?
How do you convert from moles to grams?
6.6 The Volume of a Mole of Gas
Standard Temperature and Pressure (STP)
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Chemistry
Unit 09 Chemical Quantities
Molar Volume
How do you convert from liters to moles?
How do you convert from moles to liters?
6.7 Gas Density and the Gram Molecular Mass
What is gas density usually measured in?
6.8 Converting Between Units with Moles
Draw the Mole Road
What do you always always always convert to first? _____ _____ _____ _____ _____
6.9 Percent Composition
Percent Composition
Formula for percent composition
6.10 Calculating Empirical Formula
Empirical Formula
Use Example 15 to create sets in trying to solve empirical formula problems.
1.
2.
3.
4.
6.11 Calculating Molecular Formulas
What is the difference between Empirical and Molecular Formulas?
3
Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Discussion Sheet 9a – Introductory Mole Map
NAME: ______________________
Use this Mole Map when the chemical formula does not change.
number of particles
22.4 L X
(if X is a gas at STP)
6.02 × 1023
atoms or
molecules
X
liters of a gas
grams of a substance
1 mole X
MM g X
(find the Molar Mass
in the Periodic
Table)
moles of a substance
4
Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
NAME: ______________________
SWS Molar Mass (Pg 1)
Molar mass is defined as the mass found in an atom, or molecule per unit mole. The units for molar mass are
grams/mole. To find the molar mass of elements you use the periodic table. The molar mass is the atomic mass to
two places past the decimal.
Complete the table of molar masses below using the example in the table.
Element
Carbon
Sulfur
Nitrogen
Oxygen
Hydrogen
Sodium
Chlorine
Aluminum
Fluorine
Copper
Iron
Tin
Phosphorus
Nickel
Barium
Argon
Lithium
Helium
Calcium
Atomic Mass (amu)
12.0107
Molar Mass (g/mol)
12.01
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Chemistry
Unit 09 Chemical Quantities
Finding the molar mass for a compound involves adding up all the individual atoms in the compound.
Example:
Carbon monoxide, CO, has one atom of Carbon (molar mass-12.01g/mol) and one atom of Oxygen (molar mass
16.00g/mol). The molar mass of carbon monoxide would be
12.01g/mol + 16.00g/mol=28.01g/mol
Find the following molar masses for the compounds below. Be sure to include units and proper significant figures.
Compound Name
Compound Formula
Individual Molar Mass
Carbon Dioxide
CO2
C-1 x 12.01g/mol
O-2 x 16.00g/mol
Ammonium
Carbonate
NaCl
Sulfur trioxide
MgCl2
Acetate
C6H12O6
Aluminum Chloride
Sodium Hydroxide
Copper(II) Sulfate
Molar Mass of
Compound
44.01g/mol
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Chemistry
Unit 09 Chemical Quantities
Compound Name
Compound Formula
Individual Molar Mass
Carbon Dioxide
CO2
C-1 x 12.01g/mol
O-2 x 16.00g/mol
Zinc (II) Chloride
AgNO3
NaHCO3
Potassium Perchlorate
Calcium Oxalate
Mn(C2H3O2)2
Iron (III) Oxide
Zn(SO3)
K2Cr2O7
Lead (V) Phosphate
Al(OH)3
Be(OH)2
H 2O
Molar Mass of
Compound
44.01g/mol
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
SWS MolesParticles (Pg 1)
8
NAME: ______________________
Mole Calculation Practice
Make sure you show all your work and include correct units and significant figures.
Problem
1. Determine the
number of zinc atoms
in 2.85 mol of Zn.
2. How many atoms are
in a 0.230 mol sample
of lead?
3. Calculate the number
of molecules in 11 mol
of water.
4. How many moles are
in 2.967 x 1020 atoms
iron?
5. How many moles are
5.60 x 1024 atoms of
nickel?
6. How many moles are
in a 13.79g sample of
AlCl3?
7. Determine the mass
in grams of 42.6900
mol silicon.
8. Find the number of
moles in 87.4 g of
barium.
9. Calculate the number
of grams in 2.50 mol
of silver (II) nitrate.
Converting
from…to
from moles to
number of atoms
Avogadro’s
number, Molar
mass or both
Avogadro’s number
Solve the Problem
2.85mol Zn x 6.022 x 1023atoms = 1.72
x 1024 atoms
1 mol
Chemistry
Unit 09 Chemical Quantities
Problem
10. Find the number of
molecules in 8.00 g
of sodium.
11. Convert 1.31 x 103 g
Zn to moles.
12. What is the mass, in
grams, of 1.510 x 1015
atoms of neon?
13. How many atoms are
in 11.018 g of
mercury?
14. Determine the
number of particles
in 29 g of sodium.
15. Determine the
number of moles in
367 g of magnesium.
16. Convert 1.9 mol of
xenon to grams.
17. How many moles are
in 1.276 x 1025
particles of glucose
(C6H12O6)?
18. How many molecules
are there in 24
grams of FeF3?
19. How many molecules
are there in 450
grams of Na2SO4?
20. How many grams are
there in 2.3 x 1024
atoms of silver?
Converting
from…to
Avogadro’s
number, Molar
mass or both
Solve the Problem
9
Chemistry
Unit 09 Chemical Quantities
Unit 9– Chemical Quantities
Worksheet 9.01 – Moles to Particles and Back
Convert moles to particles. Show all work.
a. 45.6 moles of CH4
b. 1.03 moles of NH3
c. 5.0 × 103 moles of H2
d. 6.02 × 10 23 moles of C 2H3O2
Convert particles to moles. Show all work.
a. 7.83 × 1024 molecules Ethanol
b. 5.02 × 1026 Au atoms
c. 24 molecules of H 2O
d. 1 atom H
NAME: ______________________
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
SWS Molesgrams (Pg 1)
1.
NAME: ______________________
Determine the number of moles for each of the following:
a. 26.32g Cu
b. 345.00g Cl
c.
75.45g Al
d. 534.25g Hg
e.
150.02g H2O
f.
55.0g Fe2O3
g.
500.0kg CaCl2
h. 1.25 x 103g Pb
i.
27.00g C12H22O11
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Chemistry
Unit 09 Chemical Quantities
SWS Molesgrams
(Pg 2)
2. Determine the mass for each of the following:
a. 1 mol S
b. 2.90 mol Fe
c.
.5 mol Zn
d. 13.87mol Au
e.
50.50mol KCl
f.
15.60mol NH4OH
g.
1 mol H2O
h. 3.5 mol CuSO4
i.
25.15 mol Na2SO3
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
NAME: ______________________
Worksheet 9.02 – Moles to Grams and Back
Calculate the molar mass of each of the following compounds. Round each mass number from
the periodic table to the nearest whole number. SHOW WORK!
CO2:12.01+16.00+16.00= 44.01 g/molH2:
Au:
HCl:
H2O:
H2SO4:
H2C 2O4:
NaCl:
SCl6:
CaCl2:
N2O5:
Mg 3N2:
P4O10:
Al2(SO4)3∙5H2O:
NaSO4:
Ca(OH)2:
Ba(C2H3O2)2:
Zn3(PO4)2:
O3:
Na3PO4:
VCl3:
Convert grams of a sample into moles. Show all work.
a. 56 grams of CO2
b. 1060 g C6H6
c. 1.24×10 3 g Au 2(SO4)3
d. 60 g O2
e. 81.5 g NH3
f. 75 g Au
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Worksheet 9.03 – More Molar Mass
NAME: ______________________
Convert grams of a sample into moles. Show all work.
a. 56 g Au
b. 76 g H2SO4
c. 600 g H2C 2O4
d. 5800 g NaCl
e. 75 g SCl 6
Convert moles of a sample into grams. Show all work.
a. 45 moles of CaCl2
b. 760 moles of N 2O5
c.
0.014 moles of Mg3N2
d. 80 moles of P 4O10
e. 1.02 moles of NaSO4
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Worksheet 9.04 – Molar Volume of a Gas
NAME: ______________________
Answer the following. Show all work.
1. What is the volume at STP of all of these gases?
a. 3.20 × 10-3 mol CO2
b. 0.960 mol CH4
c. 3.70 mol N2
2. Assuming STP, how many moles are in these volumes?
a. 67.2 L SO2
b. 0.880 L He
c. 1.00 × 10 3 L C 2H6
3. A gaseous compound composed of sulfur and oxygen that is linked to the formation of acid
rain has a density of 3.58 g/L at STP. What is the molar mass of this gas?
4. What is the density of krypton gas at STP?
15
Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Worksheet 9.04 – More Molar Mass
NAME: ______________________
Convert grams of a sample into particles. Show all work.
c. 56 g Au
d. 76 g H2SO4
c. 600 g H2C 2O4
d. 5800 g NaCl
e. 75 g SCl 6
Convert liters of a sample into grams. Show all work.
f. 45 liters of Cl2
g. 760 liters of N2O
h. 0.014 liters of N2
i. 80 liters of O 2
j. 1.02 liters of SO3
16
Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
NAME: ______________________
Worksheet 9.05 – Multiple Step Mole Conversions
Perform the following conversions. Show work.
a. Convert 56.2 g CO2 into liters of CO 2 gas at STP.
b. Convert 7.62 × 1023 molecules of N2O5 into grams of N 2O5.
c. Convert 65.3 L P 4O10 into molecules of P 4O10.
d. Convert 124 g Au(ClO 4)3 into molecules of Au(ClO 4)3.
e. Convert 45.2 L (NH 4)3PO4 into grams of (NH4)3PO4.
f. Convert 5.03 × 1024 atoms of Xe into grams of Xe.
g. Convert 112.7 g H 2O2 into L H2O2 at STP.
h. Convert 46.8 L SO3 gas into molecules SO 3.
i. Convert 65.2 g CO2 into molecules CO2.
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Discussion Sheet 9b – Advanced Mole Map
NAME: ______________________
Use this Mole Map when the chemical formula changes from X to Y.
6.02 × 1023
atoms or
molecules X
22.4 L
X
MM g X
from
Periodic
Table
6.02 × 1023
atoms or
molecules Y
1 mole X
1 mole Y
22.4 L
Y
MM g Y
from
Periodic
Table
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
NAME: ______________________
Worksheet 9.06 – Using the Advanced Mole Map
Perform the following conversions. Show all work.
a. 150 g H2SO4 into molecules of H2SO4.
b. 42 L NH3 gas into molecules of NH 3.
c. 82.5 g P 4O10 into molecules of P4O10.
d. 47.3 g P 2O5 into atoms of O.
e. 1.23×10 24 molecules of H 2O into g H.
f. 78 L O2 into g O.
g. 1000 atoms of Au into g Au.
h. 53.2 g H3PO4 into atoms of O.
i. 63 g Na2SO4 into atoms of Na.
j. 1 molecule C3H8 into atoms of H.
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
NAME: ______________________
Worksheet 9.07 – More Advanced Map Conversions
Perform the following conversions. Show all work.
a. 6.150 g H2S into atoms of H.
b. 3.1×10 6 molecules N2 gas into moles of N 2.
c. 1.42×10 31 molecules P 4O10 into grams of P.
d. 0.44 g O3 into atoms of O.
e. 12 g of H 2O into atoms H.
f. 943.38 L O2 into g O.
g. 1 atom of Au into g Au.
h. 0.55 g H3PO3 into atoms of H.
i. 16.3 L SO3 into atoms of O.
j. 1 mole C32H66 into atoms of H.
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
SWS % Composition
NAME: ______________________
Give the % composition of all elements in these compounds. Show all work!
_____________________________________________________________
1)
ammonium sulfite
% N ______
% H ______
% S ______
% O ______
________________________________________________________________
2)
aluminum acetate
% Al ______
% C ______
% H ______
% O ______
________________________________________________________________
3)
sodium bromide
% Na ______
% Br ______
________________________________________________________________
4)
copper (II) hydroxide
% Cu ______
% O ______
% H ______
________________________________________________________________
5)
magnesium carbonate % Mg ______
% C ______
% O ______
________________________________________________________________
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Chemistry
Unit 09 Chemical Quantities
6)
iron (II) phosphate
% Fe ______
% P ______
% O ______
________________________________________________________________
7)
beryllium nitride
% Be ______
% N ______
________________________________________________________________
8)
potassium cyanide
% K ______
% C ______
% N ______
________________________________________________________________
9)
manganese (III) nitrate
% Mn ______
% N ______
% O ______
________________________________________________________________
10)
lithium phosphide
% Li ______
% P ______
________________________________________________________________
11)
nickel (III) sulfate
% Ni ______
% S ______
% O ______
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Worksheet 9.08 – Percent Composition
Answer the following questions. Show all work.
NAME: ______________________
1. Find the percent composition of each of the following compounds.
a. NaHSO 4
b. (NH4)2SO4
c. C12H22O11
d. K2Cr2O7
2. In the laboratory, 9.03 g Mg combines completely with 3.48 g N to form a compound. What
is the percent composition of this compound?
3. In the laboratory, 29.0 g Ag combines completely with 4.30 g S to form a compound. What
is the percent composition of this compound?
4. 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 this compound?
5. Calculate the percent oxygen in iron (III) sulfate.
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Chemistry
Unit 09 Chemical Quantities
Unit 9– Chemical Quantities
Worksheet 9.09 – More Percent Composition
NAME: ______________________
1. Find the percent composition of each of the following compounds. Show all work.
Fe3(PO4)2
H2CO3
C6H14
Na2S
K2CO3
BaCl2
CO(NH2)2
2. Which of the following compounds has the highest iron content? Prove it.
a. FeCl 2
c. Fe(OH) 2
b. Fe(C2H3O2)3
d. FeO
24
Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
SWS Empirical Formula
NAME: ______________________
1. Tell whether each formula is an empirical formula or a molecular formula.
C5H10O5
S2Cl2
H2C2O4
C6H12O
C6H12O2
Na2SO3
CO
C6H10O4
Empirical Formulas
2. Determine the empirical formula of a compound that contains 79.9% C and 20.1% H.
3. Find the empirical formula of a compound that contains 53.70% iron and 46.30% sulfur.
4. Determine the empirical formula of a compound that contains 17.6% Na, 39.7% Cr and 42.7%O.
5. Analysis of 20.0 g of a compound containing only calcium and bromine indicates that 4.00g of calcium
are present. What is the empirical formula of the compound formed?
II. Molecular Formulas
6. Determine the molecular formula of each compound given the empirical formula and the
Molar mass.
a. empirical formula is CH; molar mass is 78.11 g/mole
25
Chemistry
Unit 09 Chemical Quantities
b. empirical formula is OH; molar mass is 34 g/mole
c.
empirical formual is NH2; molar mass is 64 g/mole
d. empirical formula is CP4S2; molar mass is 200.2 g/mole
7. A compound is known to contain 78.1 % Boron and 21.9 % Hydrogen. What is it’s molecular
formula ? The molar mass is of the compound is 27.6 g/mole.
8. A compound contains 58.8% C, 9.8 % H and 31.4 % O. If the molar mass of the compound is 102g/mole, what is
the molecular formula of the compound?
9. A sample of compound contains 40.0g C, 53.4g O and 6.6 g of H. If the molar mass of the compound is
120g/mole, what is the molecular formula of the compound?
10. A compound contains 54.5% C, 13.6% H and 31.8% N. The molar mass of the compound is 88g/mole. What
is the molecular formula?
26
Chemistry
Unit 09 Chemical Quantities
Unit 9– Chemical Quantities
Worksheet 9.10 – Empirical Formulas
NAME: ______________________
Find the empirical formulas for compounds with the following compositions:
A. 25.9% nitrogen, 74.1% oxygen
B. 94.1% oxygen, 5.9% hydrogen
C. 79.8% C, 20.2% H
D. 67.6% Hg, 10.8% S, 21.6% O
E. 27.59% C, 1.15% H, 16.09% N, 55.17% O
F. 62.1% C, 13.8% H, remainder is N
G. 81.8% C, 18.2% H
27
Chemistry
Unit 09 Chemical Quantities
Unit 9– Chemical Quantities
NAME: ______________________
Worksheet 9.11 – Percent Composition and Molecular Formulas
Answer the following. Show work whenever appropriate.
1. Calculate the percent composition of the compounds that are formed when 222.6 g N
combines completely with 77.4 g O.
2. Calculate the percent composition of table salt, if the decomposition of table salt yields 2.62
g Na and 4.04 g Cl.
3. The compound methyl butanoate smells like apples. Its percent composition is 58.8% C, 9.8%
H, and 31.4% O. Methyl butanoate’s molar mass is 102 g/mol. What is its molecular formula?
4. Calculate the percent composition of calcium acetate, Ca(C 2H3O2)2.
5. Using the results of problem 5, calculate the amount of hydrogen in 124 g calcium acetate.
6. Which of the following molecular formulas are also empirical formulas:
a.
b.
c.
d.
C5H10O5
C6H12O2
C55H72MgN4O5
C12H17ON
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Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Worksheet 9.12 – Molecular Formulas
NAME: ______________________
Answer the following. Show work whenever necessary.
1. A compound contains 44% Phosphorus and 56% Oxygen by mass, and a molecular mass of 284
g/mol. Find the molecular formula of the compound.
2. An organic compound contains 88.89% Carbon and 11.11% Hydrogen by mass. The molecular
mass of the organic compound is 54 g/mol. Find the molecular formula of the compound.
3. A compound containing only Calcium, Carbon, and Oxygen, was mined in the Rocky Mountains.
39.95% of the compound is Calcium. By mass, there is four times as much Oxygen as there is
Carbon. Find the empirical formula.
4. Iron forms an ionic compound with hydroxide (OH-1 ). 52% of the compound by mass is Iron.
Find the charge on the iron ion by finding the empirical formula.
29
Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Worksheet 9.13 – More Molecular Formulas
NAME: ______________________
Answer the following. Show work as appropriate.
1. Analysis of a compound shows that it contains 10.88 g of calcium and 19.07 g of chlorine.
Determine the empirical formula of this compound.
2. Determine the empirical formula of a compound that contains 69.5% oxygen and 30.5%
nitrogen.
3. The gram formula mass of a compound is 166.3 g. The compound contains 47.1% potassium,
14.5% carbon, and 38.4% oxygen. What is the molecular formula of the compound?
4. Determine the empirical formula of a certain copper sulfide ore if a 7.68 g sample of the
compound contains 6.13 g copper.
30
Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Worksheet 9.14 – Molar Review
NAME: ______________________
Answer the following questions. Show all work.
1. How many grams of Oxygen are in 560g of ribose, C 5H10O5?
2. What is the volume of 4g of carbon dioxide?
3. How many atoms of carbon are there in 100g of pentane, C 5H12?
4. A compound is 38.1% Oxygen, and 25.4% Sulfur by mass. The rest of the compound is
Sodium. What is the empirical formula?
5. A compound is 50% Oxygen and 50% Sulfur by mass. What is the molecular formula if the
gram molecular mass is 512g per mole?
6. What is the mass percentage of oxygen in iron (II) phosphate?
31
Chemistry
Unit 09 Chemical Quantities
Unit 9 – Chemical Quantities
Worksheet 9.15 – More Molar Review
NAME: ______________________
Answer the following questions. Show all work.
1. How many atoms of oxygen are in 73L of dinitrogen pentoxide?
2. How many liters are occupied by 10 moles of carbon monoxide gas?
3. How many grams of CaCO3 are in 75 moles?
4. How many liters of form from 5.67g of a gas at STP?
5. In an experiment, 0.009348 g of sodium chloride was used. How many atoms are in this
sample?
6. A compound containing only nitrogen and oxygen is 30.4% N by mass. The molar mass of the
compound is 92 grams per mole. What is the molecular formula of the compound?
32