Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in...
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![Page 1: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/1.jpg)
Quantities in Chemistry
The Mole and Molar Mass
![Page 2: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/2.jpg)
Mole Review• A Mole is a unit of measurement in chemistry. It
represents 6.02 x 1023 of an entity. One mole of sodium is 6.02 x 1023 atoms of sodium. The symbol of mole is “mol”.
• 6.02 x 1023 is also known as Avogadro’s constant.
![Page 3: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/3.jpg)
Molar Mass
• Molar Mass (M) is the mass (in grams) of one mole of a chemical entity.
• The formula for molar mass is:• Molar Mass (M) = mass (g) / mole (mol)• The molar mass of an element can be determined
from the periodic table. It is the same number as the atomic mass.
• For example Hydrogen’s molar mass is 1.01 g/mol
![Page 4: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/4.jpg)
Molar Mass of Compounds
• The molar mass of a compound is equal to the sum of the molar masses of the atoms in the molecules or ions in the compound.
• For example, the molar mass of water is:
• MH2O = 2(MH) + (MO)
= 2(1.01g/mol) + 1(16.0g/mol)
=18.02 g/mol
![Page 5: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/5.jpg)
Example: Find the molar mass of H2CO2
• M H2CO2 = 2(MH) + (MC) +2(MO)
= 2(1.01g/mol) + (12.00g/mol) + 2(16.0g/mol)
=46.02 g/mol
![Page 6: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/6.jpg)
Calculations Involving Atoms, Moles, Mass & Molar Mass
• It is often more convenient and practical to determine the number of atoms using mass instead of counting.
• It is easier to determine mass by using number of moles
![Page 7: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/7.jpg)
Atoms, Moles, Mass & Molar Mass Calculations
• Example 1: Calculate the molar mass of magnesium if 0.330mol has a mass of 8.02g
M=m/n
= 8.02g/0.330mol
= 24.3g/mol
![Page 8: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/8.jpg)
Atoms, Moles, Mass & Molar Mass Calculations
• Example 2: Calculate the mass, in grams, of 2.00 mol of calcium atoms.
M=m/n
m = M x n
= 40.08g/mol x 2.0 mol
= 80.2g
![Page 9: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/9.jpg)
Atoms, Moles, Mass & Molar Mass Calculations
• Example 3: How many moles of gold are in 275.8g of pure gold?
M=m/n
n = m/M
= 275.8g / 197.0 g/mol
= 1.400 mol
![Page 10: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/10.jpg)
Calculating Number of Atoms
• If you have a mass of the number of moles of an item, you can determine the number of molecules in an amount of an element using Avogadro’s number.
• Avogadro’s number = 6.02 x 1023 atoms/mol
![Page 11: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/11.jpg)
Atom Calculations• Example 4: How many atoms of gold are in a
232.8g of pure gold?• Step 1: Determine the number of moles
– n = m/M = 232.8g / 197.0g/mol = 1.182 mol
• Step 2: Using Avogadro’s number and the number of moles, determine the number of atoms.– N= n x NA = 1.182 mol x 6.02 x 1023 atoms/mol = 7.12 x 1023 atoms
![Page 12: Quantities in Chemistry The Mole and Molar Mass. Mole Review A Mole is a unit of measurement in chemistry. It represents 6.02 x 10 23 of an entity. One.](https://reader034.fdocuments.us/reader034/viewer/2022051001/5697bf6f1a28abf838c7d30d/html5/thumbnails/12.jpg)
Atom Calculations• Example 5: How many atoms of sulfur are in a
230.0g of pure sulfur?• Step 1: Determine the number of moles
– n = m/M = 230.0g / 32.06g/mol = 7.174 mol
• Step 2: Using Avogadro’s number and the number of moles, determine the number of atoms.– N= n x NA = 7.174 mol x 6.02 x 1023 atoms/mol = 4.319 x 1024 atoms