90 likes | 561 Views
Day 2 - Notes. Unit: Chemical Quantities. Measuring Mass with the Mole. After today, you will be able to…. Calculate molar mass of a substance Use molar mass to calculate the mass of a substance given then number of moles and vice versa. Atomic Mass vs. Molar Mass.
E N D
Day 2 - Notes Unit: Chemical Quantities Measuring Mass with the Mole
After today, you will be able to… Calculate molar mass of a substance Use molar mass to calculate the mass of a substance given then number of moles and vice versa
Atomic Mass vs. Molar Mass The atomic masson the Periodic Table is the mass of a single atom in amu (atomic mass units). Example: 1 carbon atom= 12.01 amu
Atomic Mass vs. Molar Mass The molar mass (MM) = mass of one mole of a substance. It is equal to the atomic mass in grams. Example: 1 mole of carbon atoms = 12.01 grams
Molar Mass Examples Example: What is the molar mass of Al2S3? 2Al = 2(26.98) = 3S = 3(32.07) = 53.96 Round molar masses two decimal places to the right! +96.21 150.17g Al2S3=1 mol Al2S3
Molar Mass Examples Example: What is the molar mass of Ba3(PO4)2? 3Ba = 3(137.33) = 2P = 2(30.97) = 8O = 8(16.00) = 411.99 61.94 +128.00 601.93g Ba3(PO4)2=1 mol Ba3(PO4)2
Example: What is the mass of 1.33 moles of Ba3(PO4)2? K: 1.33 mol Ba3(PO4)2 U: ? g Ba3(PO4)2 601.93gBa3(PO4)2 . 1.33 mol Ba3(PO4)2 x = 1 mol Ba3(PO4)2 1 801g Ba3(PO4)2
Example: How many moles are equal to 157.8g of CaCl2? K: 157.8 g CaCl2 1Ca = 1(40.08) = 2 Cl = 2(35.45) = 40.08 +70.90 U: ? mol CaCl2 110.98 1 mol CaCl2. 157.8 g CaCl2 x = 110.98 g CaCl2 1 1.422 mol CaCl2
HOMEWORK: Time to Practice!Complete WS 2