Mole Concept PDF

MOLE CONCEPT Learning Objectives: ✓ Define a mole; ✓ Illustrate Avogadro’s number with examples; ✓ Determine the molar mass of elements and compounds; ✓ Calculate the mass of a given number of moles of an element or compound, or vice versa; and ✓ Calculate the mass of a given number of particle...

MOLE CONCEPT Learning Objectives: ✓ Define a mole; ✓ Illustrate Avogadro’s number with examples; ✓ Determine the molar mass of elements and compounds; ✓ Calculate the mass of a given number of moles of an element or compound, or vice versa; and ✓ Calculate the mass of a given number of particles of an element or compound, or vice versa.  THE AVOGADRO’S NUMBER Mole (mol) - the amount of substance containing the same number of particles ✓ One mole of a substance is equivalent to the Avogadro's number, 6.02 × 10²³, named in honor of the Italian scientist, Amadeo Avogadro.  THE AVOGADRO’S NUMBER 1) 1 mole of an element is numerically equal to its atomic mass expressed in grams. 1 mol C = 12 g 2) 1 mole of an element contains 6.02 × 10²³ atoms. 1 mol Al = 6.02 × 10²³ Al atoms  THE AVOGADRO’S NUMBER 3) 1 mole of molecular compound contains 6.02 × 10²³ molecules. 1 mol H₂O = 6.02 × 10²³ H₂O molecules 4) 1 mole of ionic compound contains 6.02 × 10²³ cations and 6.02 × 10²³ anions. 1 mol NaCl = 6.02 × 10²³ Na+ 1 mol NaCl = 6.02 × 10²³ Cl-  MOLAR MASS ✓ The molar mass of a compound is the mass in grams of one mole of a substance. ✓ It is numerically equal to the sum of the masses of the elements that make up the compound. ✓ It is obtained by multiplying the number of atoms by the atomic mass of each element, and getting the sum. ✓ Unit: g/mol  MOLAR MASS Example 1 Galactose (C6H12O6), a simple sugar, can be found in milk. What is its molar mass? C 6 × 12 = 72 H 12 × 1 = 12 O 6 × 16 = 96 180 g/mol  MOLAR MASS Example 2 Sodium carbonate decahydrate (Na₂CO3 10H₂O), also known as washing soda, is widely used in cleaning substances such as laundry detergents. What is the molar mass of sodium carbonate decahydrate?  MOLAR MASS Try this! Chlorophyll (C55H72MgN4O5) is a pigment in plants that is responsible for the green color of leaves. What is the mass of chlorophyll? FORMULA MASS & MOLECULAR MASS Formula mass - used for compounds that exist as ions - expressed in amu or u; numerically equal to the molas mass expressed in grams per mole of a substance Ionic Compound Common Name Molar Mass Formula mass NaCl Table salt 58 g/mol 58 g/mol CaO Quicklime 56 g/mol 56 g/mol FORMULA MASS & MOLECULAR MASS Molecular mass - used for compounds that exist as molecules - expressed in amu or u; numerically equal to the molas mass expressed in grams per mole of a substance Molecule Common Name Molar Mass Molecular mass HC2H3O2 Acetic acid 60 g/mol 60 g/mol CO2 Dry ice 44 g/mol 44 g/mol CALCULATIONS INVOLVING FORMULAS Conversion Factors Avogadro’s number: 1 mol of X 6.02 × 10²³ X atoms (molecules or ions) or 6.02 × 10²³ X atoms (molecules or ions) 1 mol of X Molar mass: 1 mol of X mass of X mass of X or 1 mol of X CALCULATIONS INVOLVING FORMULAS A. Conversions between atoms, molecules, ions; and mass Example 1 Zinc is an essential mineral that is naturally found in food, and is also available as dietary supplement. How many atoms are there in 16.5 g of Zinc? Known: 16.5 g Zn Unknown: number of atoms of Zn CALCULATIONS INVOLVING FORMULAS Example 1 Molar mass of Zinc: 65.409 g/mol Conversion factors: 65.409 g Zn 1 mol Zn or 1 mol Zn 65.409 g Zn 1 mol Zn = 6.02 × 10²³ Zn atoms 1 mol of Zn 6.02 × 1023 Zn atoms or 6.02 × 1023 Zn atoms 1 mol Zn CALCULATIONS INVOLVING FORMULAS Example 1 Process: 1 mol of Zn 6.02 × 1023 Zn atoms 16.5 g Zn × × = 𝟏. 𝟓𝟐 × 𝟏𝟎𝟐𝟑 𝐙𝐧 𝐚𝐭𝐨𝐦𝐬 65.409 g Zn 1 mol of Zn There are 𝟏. 𝟓𝟐 × 𝟏𝟎𝟐𝟑 atoms in 16.5 g Zn. CALCULATIONS INVOLVING FORMULAS Example 2 Ammonia (NH3) is commonly used for fertilizers. How many molecules of ammonia are present in 0.334 g ammonia? Known: 0.334 g NH3 Unknown: number of molecules of NH3 CALCULATIONS INVOLVING FORMULAS Example 2 Conversion factors: Molar mass of NH3: 17 g/mol 17 g NH3 1 mol NH3 or 1 mol NH3 17 g NH3 1 mol NH3 = 6.02 × 10²³ molecules 1 mol of NH3 6.02 × 1023 molecules or 6.02 × 1023 molecules 1 mol NH3 CALCULATIONS INVOLVING FORMULAS Example 2 Process: 1 mol of NH3 6.02 × 1023 molecules 0.334 g NH3 × × = 𝟏. 𝟏𝟖 × 𝟏𝟎𝟐𝟑 𝐦𝐨𝐥𝐞𝐜𝐮𝐥𝐞𝐬 17 g NH3 1 mol of NH3 There are 𝟏. 𝟏𝟖 × 𝟏𝟎𝟐𝟑 molecules in 0.334 g NH3. CALCULATIONS INVOLVING FORMULAS Try this! Cinnamyl alcohol (C9H10O) is an organic compound which is used in the production of perfumes and deodorants. How many grams of cinnamyl alcohol are there in a sample of with 3.96 × 1019 molecules? CALCULATIONS INVOLVING FORMULAS Try this! Methane (CH4) is a major component of gas used for cooking and heating homes in many countries. How many hydrogen atoms are present in 12.6 g methane? CALCULATIONS INVOLVING FORMULAS B. Conversions between mass and moles Example 1 Ammonium nitrate (NH4NO3) is a main component of explosive mixtures used for mining and quarrying. If an explosive contains 345 g of ammonium nitrate, how many moles of ammonium nitrate are present in the explosive? CALCULATIONS INVOLVING FORMULAS Example 1 Known: 345 g of NH4NO3 Unknown: mol of NH4NO3 Conversion Factors: Molar mass of NH4NO3 = 80 g/mol 80 g NH4 NO3 1 mol NH4 NO3 or 1 mol NH4 NO3 80 g NH4 NO3 CALCULATIONS INVOLVING FORMULAS Example 1 Process: 1 mol NH4 NO3 345 g NH4NO3 × = 4.31 mol NH4NO3 80 g NH4 NO3 There are 4.31 mol NH4NO3 in 345 g NH4NO3. CALCULATIONS INVOLVING FORMULAS Example 2 Copper (Cu) is used for the absorption of iron and concerned with the formation of hemoglobin. How many grams of Cu are present in 3.87 mol copper? Known: 3.87 mol Cu Unknown: mass of Cu CALCULATIONS INVOLVING FORMULAS Example 2 Conversion Factors: Molar mass of Cu = 63.546 g/mol 63.546 g Cu 1 mol Cu or 1 mol Cu 63.546 g Cu Process: 63.546 g Cu 3.87 mol Cu × = 246 g Cu 1 mol Cu Thanks! Slidesgo CREDITS: This presentation template was created by Slidesgo, and includes Flaticon Freepik icons by Flaticon, and infographics & images by Freepik