Practice: If a sample of sodium chloride, NaCl, contains 73.1 kg, what is its number of formula units?
The Mole Concept involves the interconversions between different unit amounts of a substance.
Concept #1: Mole Concept
Mole connects together atoms, ions, molecules and formula units.
Example #1: Which of the following compounds would not be associated with the term “formula unit”?
Concept #2: Converting between Moles and Particles
Converting between moles and particles requires Avogadro's Number: 1 mole = 6.022x1023 particles.
Example #2: How many moles of chlorine gas are there in 8.33 x 1037 molecules?
Concept #3: Converting between Mass and Moles
Example #3: How many grams of chlorine gas are there in 2.34 moles?
Example #4: How many grams of Cl2 contain 9.25 x 1024 molecules of Cl2?
Mole also serves to connect mass units to particles.
Practice: If a sample of sodium chloride, NaCl, contains 73.1 kg, what is its number of formula units?
Practice: Calculate the number of oxygen atoms found in 783.9 g NiCl2 • 6 H2O.
Practice: If the density of water is 1.00 g/mL at 25°C, calculate the number of water molecules found in 1.50 x 103 µL of water.
Practice: A cylindrical copper wire is used for the fences around a house. The copper wire has a diameter of 0.0750 in. How many copper atoms are found in 5.160 cm piece? The density of copper is 8.96 g/cm3. (V = π • r2 • h)
Practice: The density of the sun is 1.41 g/cm3 and its volume is 1.41 x 1027 m3. How many hydrogen molecules are in the sun if we assume all the mass is hydrogen gas?
