Chapter 10 – The Mole

Chapter 10-1 Chemical Measurements Atomic Mass The relative mass of a single atom. All masses are relative to the carbon-12 atom. Formula Mass Sum of the atomic masses for all elements in a compound. Atomic Mass Unit (amu) General unit for the mass of an atom. Since the actual mass of an atom is so small, these are relative mass units. Relative to the mass of each atom.

Calculating Formula Mass Determine the formula mass of acetic acid, HC2H3O2. Use the periodic table to find the atomic mass of each element. Round the mass to the nearest whole number, with the exceptions of Copper and Chlorine. Cu = 63.5amu Cl = 35.5amu H : 4 x 1g = 4amu C : 2 x 12g = 24amu O : 2 x 16g = 32amu + 60 amu

Practice: Formula Mass Determine the formula mass for the following: H2SO4 (NH4)2CO3 CaClO3

The Mole The number of atoms of an element equal to the number of atoms in exactly 12.0 g of carbon-12. Referred as a counting number. 1 mole of any element = 6.02 x 10 23 atoms Avogadro’s number, there are exactly 6.02 x 1023 atoms of any element in 1 mole of that element. 1mol C = 6.02 x 10 23 atoms C 1mol H = 6.02 x 10 23 atoms H 1mol S = 6.02 x 10 23 atoms S

How big is a mole? One mole of Pennies Stacked 860 quadrillion km Quadrillion = 1 x 10 15 Width of the Milky Way Galaxy Perfect Cube 2700ft x 2700ft x 2700ft 1 Mole of Water A volume of 18 mL 18 grams

Avogadro’s Number Applies the value of mole to other particles of matter besides the atom. Ionic Compounds Formula units 1 mol NaCl = 6.02 x 10 23 formula units NaCl Molecular Compounds Molecules 1 mol CO2 = 6.02 x 10 23 molecules CO2

Molar Mass Mass in grams of 1 mole of any substance. Equivalent to the formula mass of a compound and to the atomic mass of an element. 1 mol of S = 32g S 1 mol of H2SO4 = 98g H2SO4

Determining Molar Mass Determine the formula mass and the molar mass of C6H12O6. C: 6 x 12amu = 72amu H: 12 x 1amu = 12amu O: 6 x 16amu = 96amu + Formula mass = 180 amu Molar mass = 180 g/mol

10-2 Mole Conversions 1 mol = Formula mass (or Atomic Mass) Or the Molar Mass 1 mol = 6.02 x 10 23 particles 1 mol = 22.4 L of gas at STP The mole is the central unit in converting the amount of substances in chemistry.

Mass – Mole Conversions Use 1 mol = Formula Mass conversions. Mass to Moles Conversion How many moles are in 250.g of NaCl? First determine the molar mass of NaCl Moles to Mass Conversion How many grams are in .55 moles of CO2? First determine the molar mass of CO2.

Practice Mass-Mole Determine the mass for the following substances: Determine the number of moles in the following substances: 6.60g (NH4)2SO4 Determine the mass for the following substances: 2) 6.25 mol Cu(NO3)2

Mole – Particle Conversion Use 1 mol = 6.02 x 10 23 particles Particle to Mole Conversion How many moles are equivalent to 550 molecules of SO3? Mole to Particle Conversion How many atoms are in .525 moles of Ca?

Mole – Volume(L) Conversion Use 1 mol = 22.4 L of a gas at STP only. STP, Standard Temperature and Pressure. 1mol of any gas always occupies 22.4L at STP. 0 oC and 1 atm

Mole-Volume Liters to Moles How many moles are in 12 L of CO2 at STP? Mole to Liters How many liters are equivalent to .25 moles of O2 at STP? Liters to Moles How many moles are in 12 L of CO2 at STP?

Multiple Conversions What is the mass of a single molecule of water? Determine the volume of 24.5g of Cl2 gas at STP. What is the mass of a single molecule of water?

Practice Problem #1 How many atoms of hydrogen are in 210g H?

Practice Problem #2 What is the mass, in grams, of 20 atoms of sulfur?