Tuesday, October 27, 2015

Mole concept

Measuring matter
• A mass
• A volume
• A count
Count
• One dozen = 12
• One mole = Avogadro’s number of items
• Avogadro’s number = 6.022 x 1023
Molar Mass – the mass of one mole of a substance
Determine the molar mass of the following substances.
1. Carbon C = 12.011 g/mol
2. Iron Fe = 55.847 g/mol

Converting between moles and mass.
Example: What is the mass of 5.00 mol of water?
Mass = (moles)(molar mass)
= (5.00 mol)(18.105 28 g/mol) = 90.0764
= 90.1 g/mol )
Molar Volume


• The volume occupied by one mole of a gas at STP
• STP = standard temperature and pressure
• STP = 0ÂșC and 101.3 kPa
• The molar volume of any gas at STP is 22.4 L/mol
Example: What is the volume of 3.00 mol of carbon dioxide at STP?
Volume = (moles)(molar volume)
= (3.00 mol)(22.4 L/mol)
= 67.2 L )












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