Intro Questions: Write these questions down on a separate sheet of paper so that at the end of class you can answer the questions and hand your responses in to the teacher 1.What are three methods of measuring the amount of matter? 2. How is Avagadro’s number related to the mole of a substance? 3. How is atomic mass related to the mole? 4. How is the mass of a mole of a substance calculated? 5. For what purpose, do we use the expanded mole diagram?

Three ways to measure Matter 1.Count 2.Mass 3.Volume Count – Avagadro’s Number Mass – Atomic mass Volume – 22.4 L

First We Count: Avagadro’s number is a specific quantity or count of representative particles which can be atoms, molecules, or formula units This number is 6.02 x This number is one mole – a mole is a specific quantity of matter like a dozen eggs or a cup of milk it signifies a quantity of matter So, How much is 6.02 x ?

6.02 x Watermelon Seeds: Would be found inside a melon slightly larger than the moon X Pennies: Would make at least 7 stacks that would reach the moon X 1023 Blood Cells: Would be more than the total number of blood cells found in every human on earth. 1 Liter bottle of Water contains 55.5 moles H20

So what kind of particles does Avagadro’s number “count” in chemistry? Lets make a list! How doe convert the particles counted to a mole?

Converting Number of Particles to Moles: Representative Particles x __________1mole_____________ = moles 6.02 x representative particles How many moles are in 2.80 x atoms of silicon? How many moles are in 5.23 x molecules of water?

In the same way we can turn a number of moles in to some type of particle. Number of moles x 6.02 x particles = # of particles 1 mole How many atoms are in 1.14 moles of Na? How would you find the number of atoms in 2.5 moles of water? Remember particles moles particles moles particles moles

Second We Find Mass: There is a relationship between the mole, Avagadro’s number, and mass. The atomic mass of an element expressed in grams is the mass of a mole of the element. This is known as the Molar Mass of the element. That means is you have one mole of Na you have 6.02 x atoms of sodium that weighs 23g Why 23g? Because one mole of any atom equals its atomic mass in grams. Try a few: Mg, O, Cl, C, W

How would you calculate the molar mass of a compound like water? Find the molar mass of NaCl What would be the mass of 2 moles of NaCl? Remember grams moles moles grams

Third We find Volume There is a relationship between one mole of any gas and a quantity of that gas in liters. 1 mole of gas = 22.4 L So how would we convert 55.2L of CL to moles? Remember Liters moles Moles Liters

There are three ways to convert moles 1.Moles to particles 2.Moles to grams 3.Moles to volume Likewise, you can reverse the process 1.Particles to moles 2.Grams to moles 3.Volume to moles

This type of converting is described in the expanded mole diagram seen below. Now take out your expanded mole diagram and lets see Lets make a list of the possible conversion displayed by the diagram.

Now turning to your test, lets try the sample problems 10.5 to 10.8 found on pages 298 – 302.

Now lets try the guided work-sheet. Do you see any patterns in your work? Homework – Section Questions , worksheet, quick quiz on mole conversions