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What is a MOLE?

What is a MOLE?. There are 12 items in a dozen. There are 144 items in a gross of any substance. I’m going to need a bigger shovel!. There are 6.02 x 10 23 atoms or molecules in a mole of any substance. 6.02 x 10 23 = 602, 000,000,000,000,000,000,000.

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What is a MOLE?

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  1. What is a MOLE?

  2. There are 12 items in a dozen

  3. There are 144 items in a gross of any substance

  4. I’m going to need a bigger shovel! There are 6.02 x 1023atoms or molecules in a mole of any substance

  5. 6.02 x 1023 = 602, 000,000,000,000,000,000,000

  6. A mole of standard soft drink cans would cover the surface of the Earth to a depth of over 200 miles.

  7. If you had a mole of unpopped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles.

  8. Molar mass is the weight of one mole (or 6.02 x 1023 molecules) of any chemical compounds.

  9. Molar Masses Water’s molar mass is 18 grams PVC’s molar mass is 150,000 grams

  10. How can I find the molar mass of an element? Use the element’s mass on the periodic table

  11. 12.01 Example: What is the molar mass of Carbon? Therefore, Carbon’s molar mass is….. 12.01g Carbon’s atomic mass is……

  12. 24.31 Example: What is the molar mass of Magnesium? Therefore, Magnesium’s molar mass is….. 24.31g Magnesium’s atomic mass is……

  13. 83.80 Example: What is the molar mass of Krypton? Therefore, Krypton’s molar mass is….. 83.80g Krypton’s atomic mass is……

  14. Practice Time!

  15. Now, let’s kick it up a notch!

  16. To calculate the molar mass of a compounds • First you find the molar mass of the parts of the compound and then you add. • If there are more than one of a type of atom in the compound, you multiply the number of atoms time the molar mass of the one atom, and then add all parts together.

  17. What’s the molar mass of a compound like NaCl? Molar mass of Na = 22.99 Molar mass of Cl = 35.45 22.99 +35.45 So, the Molar mass of NaCl = 58.44g

  18. What’s the molar mass of C6H12O6? Molar mass of C6= 6 x 12.01 = 72.06 12 x 1.008 = 12.096 Molar mass of H12= 6 x 16.00= 96 Molar mass of O6= So, the Molar mass of C6H12O6 = =180.156 g

  19. Practice Time!

  20. Challenge! Calculate the Molar Mass: • Ca(NO3)2 • Ca3(PO4)2 • (NH4)2SO4

  21. Percent Composition A percent is a ratio. Sometimes we want to know how much of an element is in the compound.

  22. Steps to determine percent composition • Calculate the molar mass from the formula. 2. Determine how many grams the atom of interest contributes to the compound • Divide the mass of the atom by the molar mass and multiply by 100 to get a percentage. % Composition = Mass of the element in cmpd x 100 Molar Mass of cmpd

  23. Example: Find the % of Na and Cl in NaCl Sodium Chloride, NaCl Na = 22.99g Cl = 35.45g Molar Mass = 58.44g %Na = 22.99 x 100 58.44 =39.34 % Na %Cl = 35.45 x 100 58.44 = 60.7% Cl

  24. Find the % of each element in Na2SO4

  25. Give the % composition of all the elements in Magnesium sulfite Formula

  26. Relating Moles & Mass

  27. 6.02 x 1023 atoms or molecules What you already know…. It’s the same as atomic mass. How do you determine molar mass of an atom? How big is a mole? It’s the same as the sum of the atomic masses of the parts. How do you determine molar mass of a molecule?

  28. Chemist use moles to understand relationships between reactants and products. In the lab we don’t have a balance that measures moles. We must relate grams to the number of moles.

  29. What you don’t know • How many moles are in this glass of water?

  30. What else you don’t know • Can you add 3.25 moles of water to the beaker?

  31. These two questions can be solved by using conveRsins!

  32. A Conversion is just a math equation in which you START with the data and units they give you in the problem, and then MULTIPLY by CONVERSION FACTORS until you have the right units at the end.

  33. What’s a Conversion Factor? 12 eggs 1 dozen 3 feet 1 yard It’s a FRACTION in which the TOP number and BOTTOM number mean the same thing but have different units. 1 week 7 days 6 points 1 touchdown 1 cup 8 ounces 100 yards 1 football field Write 3 of your own!

  34. Mole Conversion Molar Mass or 1 Mole 1 Mole Molar Mass

  35. How do you know which part to put on top and which part to put on bottom? 12 eggs 1 dozen Is the same thing as 1 dozen 12 eggs Because How do you know which one to use?

  36. RULE!!!! Use the conversion factor with the UNITS of the info they give you in the problem on the BOTTOM and the UNITS of what you’re LOOKING FOR on the TOP!!

  37. Steps to conversions • Write the given. • Draw a “times and a line” • Write the units you were given on the bottom • Write the units you want on top • Fill in the conversion factor (remember 1 is always with the mole) • Multiply all the numbers on the top and divide it by the numbers on the bottom.

  38. By a conversion factor that connects eggs to dozens. How many eggs in ONE dozen? So, if they tell you there are 8 dozen and ask you how many eggs there are: START with what they give you 8 dozen MULTIPLY X 12 eggs 1 dozen = 96 eggs NOTE: The “dozen” in the first number and the “dozen” in the bottom of the conversion factor will cancel each other out, leaving eggs!!!

  39. By a conversion factor that connects moles to grams. How many grams in ONE mole of hydrogen? For example: START with what they give you 3 moles MULTIPLY X 12.00 grams 1 mole C How many grams are in 3 moles of Carbon? =36.00 g NOTE: The moles in the first number and the moles in the bottom of the conversion factor will cancel each other out, leaving grams!!!

  40. By a conversion factor that connects moles to grams. How many grams in ONE mole of carbon dioxide? Another example, this time a little trickier: START with what they give you 5 moles CO2 MULTIPLY X 44.01 grams 1 mole CO2 = 220.05 g How many grams are in 5 moles of carbon dioxide (CO2)? NOTE: The moles in the first number and the moles in the bottom of the conversion factor will cancel each other out, leaving grams!!!

  41. Practice Time!

  42. How many grams are there in 350 moles of iron (Fe)? • How many grams are there in 3 moles of Lithium (Li)? • How many grams are there in 46 moles of water (H2O)? •  How many grams are there in 12.7 moles of magnesium chloride (MgCl2)? • A chemist needs 12.5 moles of sulfuric acid (H2SO4). How many grams does he need?

  43. Those problems you just finished were all “MOLES TO GRAMS ” problems because they GAVE you moles and asked you to find grams. We could, on the other hand, give you GRAMS and ask you to find MOLES. That would be a GRAMS TO MOLES problem. 2

  44. By a conversion factor that connects moles to grams. How many grams in ONE mole of carbon? For example: START with what they give you 250 grams MULTIPLY X 1 mole C 12.00 grams How many moles are in 250 grams of Carbon? = 20.83 moles NOTE: The grams in the first number and the grams in the bottom of the conversion factor will cancel each other out, leaving moles!!!

  45. By a conversion factor that connects moles to grams. How many grams in ONE mole of carbon dioxide? Another example, this time a little trickier: START with what they give you 930 grams MULTIPLY X 1 mole CO2 44.01 grams How many moles are in 930 grams of carbon dioxide (CO2)? = 21.13 moles NOTE: The grams in the first number and the grams in the bottom of the conversion factor will cancel each other out, leaving moles!!!

  46. Practice Time!

  47. How many moles are in 2.4 grams of sulfur (S)? •  How many moles are in 18.7 grams of argon (Ar)? • How many moles are in 88.1 grams of potassium chloride (KCl)? • How many moles are in 2.3 grams of nitric acid (HNO3)? • How many moles are in 11.9 grams of calcium hydroxide - Ca(OH)2? (Don’t forget! The 2 subscript applies to the O and to the H!!)

  48. How many moles are in 2.4 grams of sulfur (S)? 0. 0748 mol S •  How many moles are in 18.7 grams of argon (Ar)? 0.468 mol Ar • How many moles are in 88.1 grams of potassium chloride (KCl)? 1.18 mol • How many moles are in 2.3 grams of nitric acid (HNO3)? 0.036 mol • How many moles are in 11.9 grams of calcium hydroxide - Ca(OH)2? (Don’t forget! The 2 subscript applies to the O and to the H!!) 0.16 mol

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