2. Atoms & Elements

Mole Concept

What Is Avogadro's Number - The Mole | Chemical Calculations | Chemistry | FuseSchool

The molar mass of HCl is 36.5 g/mol, and the average mass per HCl molecule is 36.5 u. Use the fact that 1 u = 1.6605 * 102 24g to calculate Avogadro’s number.

Determine the number of moles of hydrogen atoms in each
sample.
a. 0.0885 mol C4H10

Introduction to Moles

Consider a sample of calcium carbonate in the form of a cube
measuring 2.005 in. on each edge. If the sample has a density
of 2.71 g>cm3, how many oxygen atoms does it contain?

Natural gas is a mixture of hydrocarbons, primarily methane 
1CH42 and ethane 1C2H62. A typical mixture might have 
Xmethane = 0.915 and Xethane = 0.085. Let’s assume that we 
have a 15.50 g sample of natural gas in a volume of 15.00 L 
at a temperature of 20.00 °C. 
(a) How many total moles of gas are in the sample?

How many helium atoms are there in a helium blimp containing
536 kg of helium?

Calculate the mass (in g) of each sample.
a. 5.94 * 1020 SO3 molecules

How many grams are in a mole of each of the following substances? 
(d) H2O

Which sample has the greatest mass? (LO 2.16)
(a) 5.5 mol of C 
(b) 2.1 mol of S 
(c) 4.2 mol of Be 
(d) 0.52 mol of Ag

(a) What is the mass, in grams, of 1.223 mol of iron(III)
sulfate?
(b) How many moles of ammonium ions are in 6.955 g of
ammonium carbonate?
(c) What is the mass, in grams, of 1.50 * 1021 molecules of 
aspirin, C9H8O4?

A can of diet soda contains 180 mg of the low-calorie sugar substitute aspartame (C14H18N2O5). How many molecules of aspartame are in the can of soda? (LO 3.4) 
(a) 3.7 * 10^23
(b) 3.7 * 10^20
(c) 3.2 * 10^25
(d) 1.2 * 10^22

Calculate the following quantities: 
(d) number of N atoms in 0.410 mol NH3

What is the mass of 4.91 * 1021 platinum atoms?

A drop of water has a volume of approximately 0.05 mL. How
many water molecules does it contain? The density of water is
1.0 g/cm3.

How many molecules are in each sample?
a. 6.5 g H2O

The Mole: Avogadro's Number and Stoichiometry

A sample that weighs 107.75 g is a mixture of 30% helium atoms and 70% krypton atoms. How many particles are present in the sample?

The mass of an average blueberry is 0.75 g and the mass of an
automobile is 2.0 * 103 kg. Find the number of automobiles
whose total mass is the same as 1.0 mol of blueberries.

Calculate the mass (in kilograms) of chlorine in 25 kg of each
chlorofluorocarbon (CFC).
b. CFCl3

Find the total number of atoms in a sample of cocaine hydrochloride,
C17H22ClNO4, of mass 23.5 mg.

If the atomic weight of an element is x, what is the mass in grams of 3.17 * 1020 atoms of the element?

A cube of gold that is 1.00 cm on a side has a mass of 19.3 g. 
A single gold atom has a mass of 197.0 u. (b) From the information given, 
estimate the diameter in Å of a single gold atom.

Calculate mass (in grams) of sodium in 8.5 g of each sodiumcontaining
food additive.
a. NaCl (table salt)

How many sulfur atoms are there in 5.52 mol of sulfur?

A cube of gold that is 1.00 cm on a side has a mass of 19.3 g.
A single gold atom has a mass of 197.0 u. (a) How many gold
atoms are in the cube?

How many moles of aluminum do 3.7 * 1024 aluminum atoms
represent?

The molecular formula of saccharin, an artificial sweetener, is
C7H5NO3S. (b) How
many moles of sachharin are in 2.00 mg of this substance?

Calculate the following quantities: 
(c) number of molecules in 8.447 * 10-2 mol C6H6

Concept of Mole | Avogadro's Number | Atoms and Molecules | Don't Memorise

Determine the number of moles of oxygen atoms in each
sample.
a. 4.88 mol H2O2 
b. 2.15 mol N2O 
c. 0.0237 mol H2CO3 
d. 24.1 mol CO2

The molecular formula of salicylic acid, a compound commonly
found in facial cleanser, is C7H6O3. (c) How many molecules
of salicylic acid are in 0.5 mg of this substance? 

(a) Write “true” or “false” for each statement. (b) A mole of ammonia gas 
has a mass of 17.0 g.

Calculate the mass (in g) of each sample. 
b. 9.85 * 1019 CCl2F2 molecules

Calculate the mass, in grams, of each sample. 
c. 1.8 * 1023 lead atoms

Glycine, an amino acid used by organisms to make proteins,
is represented by the following molecular model.
(c) Calculate how many moles of glycine are in a 100.0-g
sample of glycine.
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/e6cc4638e8d93178-1660309444152.jpg" alt="" />

Calculate the number of atoms in each sample.
a. 5.18 g P

A salt crystal has a mass of 0.12 mg. How many NaCl formula
units does it contain?

Calculate the mass (in g) of each sample.
a. 4.5 * 1025 O3 molecules

The molecular formula of saccharin, an artificial sweetener, is
C7H5NO3S. (c) How many molecules are in 2.00 mg of this substance?

At least 25 mg of tetrahydrocannabinol (THC), the active
ingredient in marijuana, is required to produce intoxication.
The molecular formula of THC is C21H30O2. How many
molecules?

How many fluorine atoms are present in 5.85 g of C2F4?

Counting Atoms: Intro to Moles Part 2

Calculate the number of atoms in each sample. 
a. 14.955 g Cr

A sugar crystal contains approximately 1.8 * 1017 sucrose
(C12H22O11) molecules. What is its mass in mg?

What is the mass in grams of each of the following samples? 
(a) 1.505 mol of Ti
(b) 0.337 mol of Na
(c) 2.583 mol of U

What is the mass, in kilograms, of an Avogadro’s number of 
people, if the average mass of a person is 160 lb? How does 
this compare with the mass of Earth, 5.98 * 1024 kg?

The U.S. Environmental Protection Agency (EPA) sets limits on
healthful levels of air pollutants. The maximum level that the
EPA considers safe for lead air pollution is 1.5 mg>m3. If your
lungs were filled with air containing this level of lead, how
many lead atoms would be in your lungs? (Assume a total lung
volume of 5.50 L.)

How many moles of ions are in 27.5 g of MgCl2

How many grams are in a mole of each of the following substances?
(a) Ti

Determine the number of moles (of molecules or formula units)
in each sample.
a. 55.98 g CF2Cl2

A Freon leak in the air-conditioning system of an old car releases
25 g of CF2Cl2 per month. What mass of chlorine does this car
emit into the atmosphere each year?

How many silver atoms are there in 3.78 g of silver?

Converting between moles and particles requires Avogadro's Number:1 mole = 6.022x1023&nbsp;particles.

Calculate the average mass, in grams, of one platinum atom.

(b) The mole is a unit used to represent a very large number of atoms. How many atoms are equivalent to 1 mol of atoms?

Ammonium nitrate, a potential ingredient of terrorist bombs, can be made nonexplosive by addition of diammo-nium hydrogen phosphate, (NH4)2HPO4. Analysis of such a NH4NO3 - (NH4)2HPO4 mixture showed the mass percent of nitrogen to be 30.43%. What is the mass ratio of the two components in the mixture?

Calculate the following quantities: 
(a) mass, in grams, of 0.105 mol sucrose 1C12H22O112

Mole Concept Example 3

Mole also serves to connect mass units to particles.

The “lead” in lead pencils is actually almost pure carbon, and the mass of a period mark made by a lead pencil is about 0.0001 g. How many carbon atoms are in the period?

Without doing any detailed calculations (but using a periodic 
table to give atomic weights), rank the following samples in 
order of increasing numbers of atoms: 0.2 mol PCl5 molecules, 
80 g Fe2O3, 3.0 3 1023 CO molecules.

Calculate the following quantities: 
(d) number of O atoms in 6.25 * 10-3 mol Al1NO323

Mole Concept Example 1

How many grams are in a mole of each of the following substances? 
(c) Hg

An average cup of coffee contains about 125 mg of caffeine, C8H10N4O2. How many moles of caffeine are in a cup? How many molecules of caffeine?

How many molecules are in each sample? 
b. 389 g CBr4

GCSE Chemistry - The Mole (Higher Tier)  #25

A pure copper sphere has a radius of 0.935 in. How many copper
atoms does it contain? [The volume of a sphere is (4>3)pr3 and
the density of copper is 8.96 g/cm3.]

How many atoms are present in 1.2 g of gold? (LO 2.16)
(a) 2.5 * 1021 
(b) 1.4 * 1026 
(c) 7.2 * 1023 
(d) 3.7 * 1021

(b) How many bromine atoms are present in one mole of 79Br?

If the density of water is 1.00 g/mL at 25°C, calculate the number of water molecules found in 1.50 x 103 µL of water.

(a) Write “true” or “false” for each statement. (d) A mole of MgSO4(s) contains 4 moles of oxygen 
atoms.

Calculate the mass, in grams, of each sample.
a. 1.1 * 1023 gold atoms

A sample of glucose, C6H12O6, contains 1.250 * 1021 carbon 
atoms. (c) How many moles of glucose does it contain?

The allowable concentration level of vinyl chloride, C2H3Cl,
in the atmosphere in a chemical plant is 2.0 * 10-6 g/L.
How many moles of vinyl chloride in each liter does this represent?

Without doing any detailed calculations (but using a periodic
table to give atomic weights), rank the following samples in
order of increasing numbers of atoms: 0.5 mol BCl3 molecules,
197 g gold, 6.0 3 1023 CCl4 molecules.

Determine the number of moles of hydrogen atoms in each 
sample. 
c. 2.4 mol C6H12

What is the amount, in moles, of each elemental sample? 
a. 11.8 g Ar

How many moles of anions are in 35.6 g of AlF3?

5.94 x 1056 H2 molecules

8.13 x 1057 H2 molecules

3.04 x 1058 H2 molecules

7.46 x 1059 H2 molecules

The density of the sun is 1.41 g/cm3 and its volume is 1.41 x 1027 m3. How many hydrogen molecules are in the sun if we assume all the mass is hydrogen gas?

A sample of the male sex hormone testosterone, C19H28O2,
contains 3.88 * 1021 hydrogen atoms. (b) How many molecules of
testosterone does it contain?

Determine the number of moles (of molecules or formula units) 
in each sample. 
c. 0.1187 g C8H18

Mole Concept Example 2

What is the mass in grams of each of the following samples? 
(b) 0.0015 mol of lead

Determine the number of moles (of molecules or formula units)
in each sample.
d. 195 kg CaO

What is the mass in grams of each of the following samples? 
(c) 0.0015 mol of diazepam (Valium), C16H13ClN2O

How many moles of chloride ions are in 7.75 g of FeCl3? (LO 3.4)
(a) 4.78 * 10^-2 
(b) 1.59 * 10^-2 
(c) 1.43 * 10^-1
(d) 1.91 * 10^-1

Calculate the mass, in grams, of each sample.
d. 7.9 * 1021 uranium atoms

Determine the number of moles (of molecules or formula units) 
in each sample. 
b. 23.6 kg Fe(NO3)2

(a) What is the mass, in grams, of one mole of 79Br?

The molecular formula of salicylic acid, a compound commonly 
found in facial cleanser, is C7H6O3. (d) How many 
oxygen atoms are present in 0.5 mg of salicylic acid?

Calculate the mass, in kg, of each sample. 
a. 7.55 * 1026 cadmium atoms 
b. 8.15 * 1027 nickel atoms 
c. 1.22 * 1027 manganese atoms 
d. 5.48 * 1029 lithium atoms

Mole&nbsp;connects together atoms, ions, molecules and formula units.

(b) How many moles of chloride ions are in 0.2550 g of 
aluminum chloride?

A pure titanium cube has an edge length of 2.78 in. How many
titanium atoms does it contain? Titanium has a density of
4.50 g/cm3.

How many grams are in a mole of each of the following substances? 
(b) Br2

How many bromine atoms are present in 35.2 g of CH2Br2?

What is the mass, in grams, of each elemental sample?
a. 2.3 * 10 - 3 mol Sb

Calculate the number of oxygen atoms found in 783.9 g NiCl2 • 6 H2O.

Iron(II) sulfate, FeSO4, is prescribed for the treatment of anemia. How many moles of FeSO4 are present in a standard 300 mg tablet? How many iron(II) ions?

Common brass is a copper and zinc alloy containing 37.0% zinc
by mass and having a density of 8.48 g/cm3. A fitting composed
of common brass has a total volume of 112.5 cm3. How many
atoms (copper and zinc) does the fitting contain?

How many molecules (or formula units) are in each sample?
a. 85.26 g CCl4
b. 55.93 kg NaHCO3
c. 119.78 g C4H10
d. 4.59 * 105 g Na3PO4

Titanium metal is obtained from the mineral rutile, TiO2. How many kilograms of rutile are needed to produce 100.0 kg of Ti?

If a sample of sodium chloride, NaCl, contains 73.1 kg, what is its number of formula units?

How many moles are in each of the following samples?
(a) 11.51 g of Ti
(b) 29.127 g of Na
(c) 1.477 kg of U

(c) What is the mass, in grams, of 7.70 * 1020 molecules of 
caffeine, C8H10N4O2?

What is the mass, in kilograms, of an Avogadro’s number of
people, if the average mass of a person is 160 lb?

Calculate the mass (in kilograms) of chlorine in 25 kg of each
chlorofluorocarbon (CFC).
a. CF2Cl2

(b) How many molecules of C13H18O2 are in this tablet?

Calculate the following quantities:
(c) number of molecules in 1.0 * 10-6 mol CH3CH2OH

How many molecules of ethanol (C2H5OH) (the alcohol in alcoholic
beverages) are present in 145 mL of ethanol? The density
of ethanol is 0.789 g/cm3.

Determine the number of moles of hydrogen atoms in each 
sample. 
d. 1.87 mol C8H18

What is the mass in grams of each of the following samples? 
(a) 0.0015 mol of sodium

How many carbon atoms are there in a diamond (pure carbon)
with a mass of 52 mg?

A copper wire having a mass of 2.196 g was allowed to react with an excess of sulfur. The excess sulfur was then burned, yielding SO2 gas. The mass of the copper sulfide produced was 2.748 g.
(c) Calculate the number of copper ions per cubic centimeter if the density of the copper sulfide is 5.6 g/cm3.

Calculate the following quantities:
(a) mass, in grams, of 1.50 * 10-2 mol CdS

Mole Concept Example 4

The molecular formula of saccharin, an artificial sweetener, is 
C7H5NO3S. (d) How many C atoms are present in 2.00 mg of saccharin?

Calculate the following quantities:
(b) number of moles of NH4Cl in 86.6 g of this substance

(a) What is the mass, in grams, of 2.50 * 10-3 mol of
ammonium phosphate?

What is the mass, in grams, of each elemental sample? 
c. 43.9 mol Xe

Very small semiconductor crystals, composed of approximately
1000 to 10,000 atoms, are called quantum dots.
Quantum dots made of the semiconductor CdSe are now
being used in electronic reader and tablet displays because
they emit light efficiently and in multiple colors, depending
on dot size. The density of CdSe is 5.82 g/cm3.
(b) CdSe quantum dots that are 2.5 nm in diameter emit
blue light upon stimulation. Assuming that the dot is a
perfect sphere and that the empty space in the dot can
be neglected, calculate how many Cd atoms are in one
quantum dot of this size.

(a) Write “true” or “false” for each statement. (a) A mole of
ducks contain a mole of feathers.

A cylindrical copper wire is used for the fences around a house. The copper wire has a diameter of 0.0750 in. How many copper atoms are found in 5.160 cm piece? The density of copper is 8.96 g/cm3. (V = π • r2 • h)

The Most Common Mistake with Moles!

Learn the toughest concepts covered in Chemistry with step-by-step video tutorials and practice problems by world-class tutors

Jules

General Chemistry

https://static.studychannel-prd.pearsonprd.tech/courses/general-chemistry/thumbnails/general-chemistry

#FFFFFF

The Organic Chemistry Tutor

Don't Memorise

Cognito

FuseSchool - Global Education

Tyler DeWitt

Jules Bruno

Professor Dave Explains

1. Intro to General Chemistry

3. Chemical Reactions

4. BONUS: Lab Techniques and Procedures

5. BONUS: Mathematical Operations and Functions

6. Chemical Quantities & Aqueous Reactions

7. Gases

8. Thermochemistry

9. Quantum Mechanics

10. Periodic Properties of the Elements

11. Bonding & Molecular Structure

12. Molecular Shapes & Valence Bond Theory

13. Liquids, Solids & Intermolecular Forces

14. Solutions

15. Chemical Kinetics

16. Chemical Equilibrium

17. Acid and Base Equilibrium

18. Aqueous Equilibrium

19. Chemical Thermodynamics

20. Electrochemistry

21. Nuclear Chemistry

22. Organic Chemistry

23. Chemistry of the Nonmetals

24. Transition Metals and Coordination Compounds

[BOOK CHEM] Clutch Version

Millikan Oil Drop Experiment

The Oil Drop Experiment helped with determining the fundamental charge of the electron.&nbsp;

Ions

Ions represent elements that possess either a positive charge or a negative charge.&nbsp;

Periodic Table: Charges

Elements lose or gain electrons to have the ideal number of outer shell electrons like the noble gases.&nbsp;

Law of Definite Proportions

"Different samples of a pure chemical compound always contain the same proportions of elements by mass."

Periodic Table: Classifications

The Periodic Table contains 3 Major Classifications when describing its elements

Isotopes

Isotopes are atoms of an element that have the same atomic number, but different mass number.&nbsp;

The Atom

The atom represents the basic functional unit in chemistry

The Mole Concept involves the interconversions between different unit amounts of a substance.

Periodic Table: Representative Elements & Transition Metals

The Groups of the Periodic Table can be broken down into the Representative Elements and Transition Metals

Atomic Theory

John Dalton, one of the "Fathers of Chemistry"is credited with modernizing the Atomic Theory.

Subatomic Particles

The atom is composed of 3 subatomic particles:neutrons, protons, and electrons.

Periodic Table: Elemental Forms

The elements of the Periodic Table exist in different elemental forms in the natural world

Periodic Table: Phases

Under standard conditions of temperature and pressure, the elements can exist as solids, liquids or gases

Atomic Mass

The atomic mass of an element includes the masses of all 3 subatomic particles of neutrons, protons and electrons.&nbsp;

Periodic Table: Group Names

The Periodic Table can be further classified into Periods and Groups.&nbsp;

Law of Conservation of Mass

"In a chemical reaction, no matter is created or destroyed, but instead changes form."

Calculating Molar Mass

Molar Mass is a physical property that represents the mass of a substance divided by the amount of that substance.