11

Conserving Matter

Read Conserving Matter: p.153

Do the Reading Guide- tape it into your CB when it is complete!

22

Warm Up-

Make sure your reading guide is complete and taped in you CB.

33

C.2 Accounting for Atoms

The law of conservation of matter says that “matter is neither created nor destroyed”.

44

Chemical Equations

In a chemical reaction, the number of atoms of each element needs to be the same on both sides of the arrow.

Reactants Products

CH4 + O2 CO2 + H2O

55

Balancing an Equation

CH4 + O2 CO2 + H2O

a. Count the atoms on each side of the equation.b. Place coefficients in front to make the sides equal.c. Recheck to make sure it worked

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Try these!

a. NH3 H2 + N2

b. CaCO3 CaO + CO2

c. HCl + Ca(OH)2 CaCl2 + H2O

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How do I read a chemical equation?

CaCO3 CaO + CO2

One formula unit of calcium carbonate reacts to form one formula unit of calcium oxide and one molecule of carbon dioxide.

One mole of calcium carbonate reacts to form one mole of calcium oxide and one mole of carbon dioxide.

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Work on the balancing equations WS

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The MoleThe Mole

6.02 X 6.02 X 10102323

1010

Read C.5, p.161

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The mole is a unit of measureThe mole is a unit of measureThe mole is a unit of measureThe mole is a unit of measure

Developed Developed because it is because it is impossible to impossible to work with work with individual atoms individual atoms or molecules.or molecules.

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The MoleThe Mole• A counting unit• Similar to a dozen (except instead of

12, it’s 602 billion trillion 602,000,000,000,000,000,000,000)

• 6.02 X 1023 particles/mole (in scientific notation)

• This number is named in honor of Amedeo _____________ (1776 – 1856)Amedeo _____________ (1776 – 1856), who studied quantities of gases and discovered that no matter what the gas was, there were the same number of molecules present

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Just How Big is a Mole?Just How Big is a Mole?

• Enough soft drink cans to cover the surface of the earth to a depth of over 200 miles.

• If you had Avogadro's number of unpopped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles.

• If we were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole.

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Where Did it Come From?Where Did it Come From?

• It was NOT just picked! It was MEASURED.

• One of the better methods of measuring this number was the Millikan Oil Drop Experiment

• Since then we have found even better ways of measuring using x-ray technology

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You must know…

A mole of anything = 6.02 x 1023 particles

Look! I have a bunch of samples for you to look at!

It took me all break to count all these particles!

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Look at the periodic table!

The atomic mass of each element is written below the element symbol.

The units on atomic mass are grams per mole (g/mol)

So we have a bunch of conversion factors for doing cool calculations!

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Conversion Flow Chart

1818

Convert

1. Convert 6.17g of carbon to moles

2. Convert 2.3g Na to moles

3. Convert 0.05 moles of Cl to grams.

1919

Warm Up

Convert the following:

a. 3.4 g of nitrogen to moles

b. 0.72mol of fluorine to grams

c. 10.9 g of magnesium to moles.

2020

Molar Mass

The molar mass of a compound is the sum of the atomic masses of all the atoms in the compound.

2121

Find the Molar Mass of Calcium Chloride

CaCl2

The process1. List how many atoms of each element?2. Determine the atomic mass of each element.3. Multiply by the number of atoms4. Add them up!

2222

You learned to do this last semester!

Calculate the molar mass of carbon dioxide?

CO2

2323

Now try dinitrogen tetroxideN2O4

Remember the process

1. How many atoms of each element?

2. What is the atomic mass of each element.

3. Multiply by the number of atoms

4. Add them up!

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How did you do?

N2 O4

2 Nitrogen x 14.01 = 28.02 g/mol

4 Oxygen x 16.0 = 64.00 g/mol

• 1 mole of N2O4 = 92.02 g/mol

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More Practice!

Do C.6 in your CB

p. 163

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Convert the following

1. 6.2g of NaCl to moles

2. 3.6 g of water to moles

3. 1.20mol to water to grams

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Moles and Mass WS

Work on the WS…

Change the #5 to just say CuSO4

(Cross out the 5H2O)

2828

Conversions using Avagadros Number

How many atoms in 1.2 moles of Cu?

How many atoms in 0.5 moles of Carbon?

How many atoms in 1.3 mol of Li?

2929

Going backwards

How many moles in 3.2 x 1023 atoms of C?

How many moles in 5.6 x 1022 atoms of F?

How many moles in 5.6 x 1022 molecules of water?

3030

The Mole and Avagadros number WS

Work on the WS…

3131

Going all the way!

How many atoms in 0.30g of Lithium?

How many molecules in 3.7g of water?

3232

How many grams in 4.31 x 1023 atoms of Cu?