Presentation on theme: "The Mole Avogadro’s Number. What is a Mole? The mole is a counting unit, similar to 1 dozen. 1 dozen eggs = 12 eggs 1 mole of eggs = 6.02x10 23 eggs."— Presentation transcript:
The Mole Avogadro’s Number
What is a Mole? The mole is a counting unit, similar to 1 dozen. 1 dozen eggs = 12 eggs 1 mole of eggs = 6.02x10 23 eggs. One mole of anything means 6.02x10 23 of that thing. A mole of soda cans would cover the entire surface of the planet to a depth of 200 miles.
How do we use the mole? We use the mole to measure substances on the macroscopic scale. If we were to try and do a reaction with 100,000 carbon atoms, it would only have a mass of 1.995x g. Good luck trying to find a scale that precise. Instead we can talk about reacting moles of substances. Ex. 2 moles of Hydrogen gas reacts with 1 mole of Oxygen gas to form 2 moles of gaseous water. As a chemical reaction formula, it looks like this: 2H 2 (g) + O 2 (g) 2H 2 O(g) The coefficients in front of the substances correspond to the number of moles of each reactant and product.
A mole of particles 1 mole of C atoms = 6.02x10 23 C atoms 1 mole of CO 2 molecules = 6.02x10 23 CO 2 molecules, but That also means it has 6.02x10 23 C atoms and 12.04x10 23 O atoms 1 mole of NaCl has both 6.02x10 23 Na + ions and 6.02x10 23 Cl - ions
The mole as a conversion factor Also…
Example How many atoms of Calcium are there in 0.25 mol of Ca? Set up your DA Table. = 1.5 x atoms Ca
Example 2 If you have 4.53x10 22 molecules of CaO, how many moles of CaO do you have? =7.52x10 -2 mol
Example 3 If you have 1.2mol Na 2 CO 3, how many moles of each type of atom do you have? How many total atoms do you have? Look at the mole ratio. In each molecule of Na 2 CO 3, there are 2 Na’s, 1 C, and 3 O’s. Moles of Na = 1.2 mol x 2 = 2.4mol Na Moles of C = 1.2 mol x 1 = 1.2mol C Moles of O = 1.2 mol x 3 = 3.6mol O Total moles = 2.4mol + 1.2mol + 3.6mol = 7.2mol Total atoms =
Stoichiometry Dealing with the quantity of reactants and products. Basically, “If you have a certain amount of reactants, how much products can you produce?” Use the mole as the basis of conversion. All roads lead to The Mole