IIIIIIIV Ch. & 7 – The Mole I. Molar Conversions

Why learn about the mole? n It’s not practical to do chemical reactions by counting the number of atoms or molecules out, bc you would be counting for a VERY long time. n WE use the mole like you would a dozen, a ream, a bushel, etc….

A. What is the Mole? n A counting number (like a dozen) n Avogadro’s number n 1 mol =  anything n One mole of anything is the amount of substance that contains the same number of items as there are atoms in exactly 12 g of Carbon ,200,000,000,000,000,000,000,000 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! n 1 mole of basketballs would fill a bag the size of the earth!

B. Molar Mass n The atomic mass of an element in grams 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

B. Molar Mass Examples n carbon n aluminum n zinc

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

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

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

C. Molar Conversion Examples 1. How many oxygen atoms are present in 1.00 mol of oxygen molecules? 2. How many moles of sodium hydroxide (NaOH) are there in 1.00 kg of sodium hydroxide?