1 / 38

What’s up with the Mole?

Learn how to measure matter using moles and molar mass. Understand Avogadro's number and convert between moles and particles. Calculate molar mass and convert moles to mass.

rlaird
Download Presentation

What’s up with the Mole?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. What’s up with the Mole?

  2. How do we measure matter? pound By weight: We buy bananas by the _______________. By volume: Milk is sold by the ____________________. By counting: There are ________ students in class. gallon

  3. Many words are used to express a specific quantity. • Pair = • Dozen = Chemical Quantities 2 12

  4. How do we measure matter? • What if I wanted to know how many ATOMS were in this copper penny? Would you like to count? Could you?

  5. Avogadro’s Number • You can count particles if you introduce a term that represents a specified number of particles. • In chemistry, the term used to express a specific number of particles is a mole.

  6. Avogadro’s Number • 1 mole = 6.02 x 1023particles • That’s 602,000,000,000,000,000,000,000 • A very large number!

  7. Avogadro’s Number This number is known as Avogadro’s number, named after Amedeo Avogadro (an Italian physicist and mathematician).

  8. HOW LARGE IS IT??? • 1 mole of hockey pucks would equal the mass of the moon! • 1 mole of pennies would cover the Earth 1/4 mile deep!

  9. Representative Particles Representative particles are units used to measure the number of particles in a sample of an element or compound.

  10. Representative Particles What is the representative particle for each of these substances? • copper • sodium chloride • water atom formula unit molecule

  11. MOLE • A mole is the SI unit that measures the amount of a substance. • A mole can be related to: • number of particles • mass • volume of a gas

  12. one mole Avogadro’s number of particles mass in grams using the periodic table 22.4 L of a gas

  13. MOLE • Use dimensional analysis to convert: • moles to molecules • moles to atoms • moles to formula units • moles to grams • grams to atoms • and many more….

  14. MOLE When converting between moles and particles, the conversion factor to remember is: 1 mol = 6.02 x 1023 particles The particle unit can be atoms, molecules, or formula units.

  15. Mole/Particle Examples 1. How many moles are in 3.25 X 1020 atoms of lead? 1 mol = 6.02 x 1023 atoms 3.25 x 1020 atoms Pb 1 molPb 6.02 x 1023 atoms Pb = 5.398671 x 10-4 = 5.40 x 10-4molPb

  16. Mole/Particle Examples 2. How many molecules are there in 8.3 moles of sugar (C12H22O11)? 1 mol = 6.02 x 1023 molecules 8.3 mol C12H22O11 6.02 x 1023molec. C12H22O11 1 mol C12H22O11 = 4.9966 x 1024 = 5.0 x 1024molec. C12H22O11

  17. Mole/Particle Examples 3. How many atoms are in 0.425 mol sulfur? 1 mol = 6.02 x 1023 atoms 0.425 mol S 6.02 x 1023 atoms S = 2.5585 x 1023 1 mol S = 2.56 x 1023 atoms of S

  18. Mole/Particle Examples 4. How many moles are in 5.42 x 1022 formula units of NaCl? 1 mol = 6.02 x 1023 atoms 1 molNaCl 5.42 x 1022 Form. U NaCl 6.02 x 1023 Form. U NaCl = 0.090033222 = 0.0900 molNaCl

  19. Molar Mass molar mass – the mass in grams of one mole of an elementor compound.

  20. Terms that Describe the Mass of a Substance • Atomic mass – mass of one atom of an element (unit = amu) • Molecular mass - mass of one molecule of a covalent compound (unit = amu) • Formula mass - mass of one formula unit of an ionic compound (unit = amu) •  Molar mass - mass of one mole of an element or compound (unit = g/mol).

  21. Molar Mass To calculate molar mass: • Obtain all of the masses of the involved elements from the periodic table. • Multiply each element’s mass by the subscript. • Add the resulting products. • Round the answer to the proper number of decimal places.

  22. Molar Mass of Element Examples • Aluminum = • Zinc = 26.982 = 26.98 g/mol 65.38 g/mol

  23. Molar Mass of Compounds Examples P2O5 • Diphosphorus pentaoxide P = X 2 = 61.948 30.974 + O = 15.999 X 5 = 79.995 141.943 = 141.94 g/mol

  24. Molar Mass of Compounds Examples +3 -1 Al(OH)3 • Aluminum Hydroxide Al = X 1 = 26.982 26.982 O = 15.999 X 3 = 47.997 + H = 1.008 X 3 = 3.024 78.003 = 78.00 g/mol

  25. Molar Mass of Compounds Examples +2 -3 Ba3(PO4)2 • Barium phosphate Ba = = 411.984 137.328 X 3 P = = 61.948 30.974 X 2 + = 127.992 O = X 8 15.999 = 601.92 g/mol 601.924

  26. Moles to Mass • Use dimensional analysis to convert • moles to mass or mass to moles. • Mass unit = grams • Conversion Factor to Remember: • 1 mol = molar mass of the element or compound (molar mass = g/mol) found on the periodic table

  27. Moles to Mass Examples • How many moles of carbon are in 26 g of carbon? Carbon: 1 mol = 12.01 g (from PT) 26 g of C 1 mol of C = 2.164862614 12.01 g of C = 2.2 mol of C

  28. Moles to Mass Examples • How many grams are there in 2.37 moles of CO2? C = 12.011 x 1 O = 15.999 x 2 = 12.011 = 31.998 + 44.009 g = 1 mol 44.01 g CO2 2.37 molCO2 = 104.3037 1 mol CO2 = 104 g CO2

  29. Moles to Mass Examples • How many moles are present in 142.1 grams of NaCl? Na = 22.990 x 1 Cl = 35.453 x 1 = 22.990 = 35.453 + 58.443 g = 1 mol 1 molNaCl 142.1 g NaCl = 2.43155373 58.44 g NaCl = 2.432 molNaCl

  30. Moles to Mass Examples • How many grams are in 3.34 moles of potassium bromide? +1 -1 KBr K = 39.098 x 1 Br = 79.904 x 1 = 39.098 = 79.904 + 119.002 g = 1 mol 119.00 g KBr 3.34 molKBr = 397 g KBr = 397.46 1 molKBr

  31. Molar Volume of a Gas • The volume of a gas changes as the temperature and pressure change, so the volume is usually measured at standard temperature and pressure. • STP = abbreviation for standard temperature and pressure • Standard temperature = 0oC = 273 K • Standard pressure = 1 atm or 101.3 kPa

  32. Molar Volume of a Gas • At STP, one mole of any gas occupies the same volume: 22.4 L.

  33. Molar Volume of a Gas • Use dimensional analysis to convert: • volume (liters) to moles • or moles to volume (liters) • Conversion Factor to Remember: • 1 mole = 22.4 L

  34. Molar Volume of a GasExamples • Determine the volume, in liters, of 0.60 mol SO2 gas at STP.

  35. Molar Volume of a GasExamples • Assuming STP, how many moles are in 67.2 L SO2?

  36. Molar Volume of a GasExamples • How many moles are in 1.0 x 103 L of C2H6?

  37. Molar Volume of a GasExamples • What is the volume at STP of 3.20 x10-3 mol CO2?

  38. Mole Calculations Learned # of Particles (atoms, molecules, formula units) 1 mol = 6.02 x 1023 particles Liters of gas at STP 1 mol = 22.4 L MOLES 1 mol = mass from Periodic Table Mass (grams)

More Related