IIIIIIIV Unit 6 - The Mole I. Molar Conversions

A. What is the Mole? n A counting number (like a dozen) n Avogadro’s number (N A ) n 1 mol = 6.02  items A large amount!!!!

n 1 mole of hockey pucks would equal the mass of the moon! A. What is the Mole? n 1 mole of pennies would cover the Earth 1/4 mile deep! E.C. ($) n 1 mole of basketballs would fill a bag the size of the earth!

EC Hints n 5.1×10 8 km 2 = surface area of Earth n Find diameter and width of penny in mm n 0.25 miles = __?__ mm n How much $$$ do we have here???

Mole Humor n Q: What is a mole's favorite movie? n Q: What did Avogadro teach his students in math class? n Why was there only one Avogadro?

B. Molar Mass n Mass of 1 mole of an element or compound. n Atomic mass tells the...  atomic mass units per atom (amu)  grams per mole (g/mol) n Round to 2 decimal places (hundredths; ie: )

B. Molar Mass Examples n carbon n aluminum n zinc g/mol g/mol g/mol

B. Molar Mass Examples n water n sodium chloride H2OH2O  2(1.01) = g/mol  NaCl  = g/mol

B. Molar Mass Examples n sodium bicarbonate n sucrose  NaHCO 3  (16.00) = g/mol  C 12 H 22 O 11  12(12.01) + 22(1.01) + 11(16.00) = g/mol

Mole Humor n What did Avogadro invent for his wife to use as a night cream? n How much does Avogadro exaggerate? n What is Avogadro's favorite kind of music?

C. Molar Conversions molar mass (g/mol) MASS IN GRAMS MOLES NUMBER OF PARTICLES 6.02  (particles/mol)

C. Molar Conversion Examples Grams Moles n How many moles of carbon are in 26 g of carbon? 26 g C 1 mol C g C = 2.2 mol C

C. Molar Conversion Examples Moles Grams n How many grams are in 21.3 moles of CO moles CO g 1mol CO 2 = 937 g CO 2

C. Molar Conversion Examples Moles Molecules n How many molecules are in 2.50 moles of C 12 H 22 O 11 ? 2.50 mol 6.02  molecules 1 mol = 1.51  molecules C 12 H 22 O 11

C. Molar Conversion Examples Molecules Moles n Convert 1.75 x atoms of K to moles of K x atoms K 1 mol 6.02  molecules K = 291 mol K

C. Molar Conversion Examples Molecules Grams n Find the mass of 2.1  molecules of NaHCO  molecules 1 mol 6.02  molecules = 290 g NaHCO g 1 mol

IIIIIIIV III. Formula Calculations Unit 6 – The Mole

A. Percentage Composition n the percentage by mass of each element in a compound

 100 = A. Percentage Composition %Cu = g Cu g Cu 2 S  100 = %S = g S g Cu 2 S % Cu 20.15% S n Find the % composition of Cu 2 S.

C. Johannesson B. Empirical Formula C2H6C2H6 CH 3 reduce subscripts n Smallest whole number ratio of atoms in a compound

C. Molecular Formula n “True Formula” - the actual number of atoms in a compound CH 3 C2H6C2H6 empirical formula molecular formula ?

Molecular vs. Empirical Formulas