7648568.ppt
- 1. Moles, Avogadro’s Number and Molar Mass Converting moles to molecules, atoms, and particles
- 2. Can anyone define the term mole?
- 3. a) 1 dozen = 12 units b) 1 pair = 2 units Daily life – we used: To delegate a big quantity: Definition Chemistry- mole concept: Mole is a substance quantity that contain a number of particles such as atom, ion, or molecule that have equal number of atom in 12 gram of 12C or 6.02 x 1023 particles
- 4. Example: 1 year = 12 months 1 month = 30 days 1 kg = 1000 g 1 km = 1000 m 1 dozen oxygen atoms = 12 oxygen atoms 1 mole oxygen atoms = 6.02 x 1023 oxygen atoms 1 mole sodium atoms = 6.02 x 1023 sodium atoms 1 mole carbon atoms = 6.02 x 1023 carbon atoms Daily life Chemistry
- 5. Mole SI unit used to measure the amount of a substance equal to 6.02 x 1023 atoms, molecules, or particles Avogadro’s number Abbreviated by mol
- 6. Avogadro’s Number 6.02 X 1023 Used to count extremely small particles Named in honor of Italian physicist Amedeo Avogardo Determined the volume of one mole of a gas
- 7. Conversions
- 8. Mole Molecules, Atoms, or Particles In order to convert moles to molecules atoms, or particles, you have to MULTIPLY the number of moles by Avogadro’s number (6.02 x 1023) Example: How many atoms are there in 4.0 moles?
- 9. How many atoms are there in 4.0 moles? Moles Atoms…MULTIPLY BY AVOGADRO’S NUMBER 2.4 x 1024 atoms
- 10. Molecules, Atoms, or Particles Moles In order to convert molecules, atoms, or particles to moles, you have to DIVIDE the number of moles by Avogadro’s number (6.02 x 1023) Example: How many moles are there in 7.14 x 1023 molecules?
- 11. How many moles are there in 7.14 x 1023 molecules? Molecules Moles…DIVIDE BY AVOGADRO’S NUMBER 1.19 moles
- 12. Practice
- 13. How many molecules are there in 3.5 moles? Moles Molecules…MULTIPLY BY AVOGADRO’S NUMBER 2.11 x 1024 molecules
- 14. How many particles are there in 9.6 moles? Moles Particles…MULTIPLY BY AVOGADRO’S NUMBER 5.78 x 1024 particles
- 15. How many moles are there in 5.75 x 1024 atoms? Atoms Moles…DIVIDE BY AVOGADRO’S NUMBER 9.55 moles
- 16. How many moles are there in 3.58 x 1023 particles? Molecules Moles…DIVIDE BY AVOGADRO’S NUMBER 0.59 moles
- 17. Molar Mass
- 18. Molar Mass the mass in grams of one mole of any pure substance In other words, the molar mass of any element is equivalent to the atomic mass of that element in units of grams per mole; g/mol
- 19. Calculating Molar Mass - To calculate the molar mass of a substance, you add the atomic mass of every element in the compound The total atomic mass is the molar mass of the substance.
- 20. Example What is the molar mass of N? Step 1: determine the atomic mass N: 14 Step 2: add units g/mol molar mass = 14 g/mol
- 21. Example What is the molar mass of CO2? Step 1: determine the mass of each element C: 12 O: 16 X 2 Step 2: add the masses to get the total atomic mass 12+16+16=44 Step 3: add units g/mol Molar mass = 44 g/mol
- 22. Practice What is the molar mass of NaCl? 58.5 g/mol What is the molar mass of H3O? 19 g/mol What is the molar mass of H2SO4? 98 g/mol
- 24. Review Mole SI unit used to measure the amount of a substance Abbreviate by mol Molar mass total atomic mass of every element in the compound Units: g/mol
- 25. What is the molar mass of NH3? Step 1: determine the mass of each element N: 14 H:1 X 3 Step 2: total the masses 14+3=17 Step 3: attach the units 17g/mol
- 26. Mole Gram Conversions When given the number of moles, MULTIPLY by the molar mass of the substance. What is the mass of 5 moles of H2O?
- 27. What is the mass of 5.O moles of H2O? Step 1: Write the given Step 2: Multiply by molar mass Step 3: Cancel the units Step 4: Solve 90 grams H2O
- 28. Gram Mole Conversions When given the number of moles, DIVIDE by the molar mass of the substance. How many moles are equivalent to 50g N?
- 29. How many moles are equivalent to 50g N? Step 1: Write the given Step 2: Divide by the molar mass Step 3: Cancel the units Step 4: Solve 3.57 moles N
- 30. Practice
- 31. What is the mass of … 2.22 mol Ti 106 g Ti 1.22 X 1023 mol Ag 1.32 X 1025 g Ag 4.5 mol H2SO4 441 g H2SO4
- 32. How many moles are consumed in… 5.62 g Kr 0.0669 mol Kr 55 g As 0.73 mol As 7.5 g NaCl 0.128 mol NaCl
- 33. Particles Gram Conversions Remember, particles, atoms, and molecules are all the same To convert particles to grams… 1st: convert particles to moles 2nd: convert moles to grams
- 34. Review When converting from moles to atoms, molecules, or particles, you must MULTIPLY by Avogadro’s number. When converting atoms, particles, or molecules to moles, you must DIVIDE by Avogadro’s number.
- 35. What is the mass of 2.5 X 1023 atoms of H2O? Step 1: convert atoms to moles Step 2: convert moles to grams
- 36. Grams Particles Conversions Once again, remember particles, atoms, and molecules are all the same To convert grams to particles… 1st: grams to moles 2nd: convert moles to particles
- 37. How many molecules are in 4.5 g C? Step 1: Convert grams to moles Step 2: Convert moles to molecules
- 38. Practice How many grams are in 5.0 X 1024 atoms of K? What is the mass of 8.5 X 1023 molecules of NH2? How many particles are in 3.75 g Ca? How many molecules are in 96 g HBr2?