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. Count2. Mass3. 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 1023

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 1023?

6.02 x 1023  Watermelon Seeds: Would be found inside a melon slightly larger than the moon.

6.02 X 1023  Pennies: Would make at least 7 stacks that would reach the moon.

6.02 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!

1.

2.

3.

How doe convert the particles counted to a mole?

Converting Number of Particles to Moles:

Representative Particles x __________1mole_____________ = moles 6.02 x 1023 representative particles

How many moles are in 2.80 x 1024 atoms of silicon?

How many moles are in 5.23 x 1018 molecules of water?

In the same way we can turn a number of moles in to sometype of particle.

Number of moles x 6.02 x 1023 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 1023 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 quantityof 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 diagramseen below. Now take out your expanded mole diagram and lets seeLets make a list of the possible conversion displayed by the diagram.

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

Now lets try the guided work-sheet. Do you see any patterns in your work?

Homework – Section Questions 10.1 -10.2, worksheet, quick quiz on mole conversions