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Avogadro’s Number

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6.02x1023

mole = (mol) 602000000000000000000000

- A mole is just a number like…
Pair = 2Trio = 3

Dozen = 12Baker’s dozen = 13

Gross = 144Score= 20

Century=100Ream=500

There are ~ 6.6 billion people on Earth

How many Earths would it take to equal the population

of 1 mole?

9.12 x 1013

- If you spent $800 billion dollars a day how many years would it take to spend a MOLEion dollars?

2.06 x 109 years

- If you had a mole of cats . . .
They would create a sphere

larger than

Earth!

- If you had a mole of H2O could you swim in it?
NO!

Water molecules are so small

that a mole of H2O = 18ml

- In chemistry we don’t work with individual atoms or molecules because they are too small to be weighed or measured
- We have to work with LOTS of atoms in order to measure them
THAT’s WHERE THE

MOLE COMES IN!

- There are more atoms in one gram of salt than grains of sand on all the beaches
of all the oceans in all

the world.

of the

in

- mass is in grams of 1 mole of atoms of an element
- In other words……
1 mol C atoms = 6.02 x 10 23 C atoms = 12g C

PracticeRemember . . .1 mole = 6.02x1023atoms or molecules =______ g from the periodic table

Stoichiometry of Chemical Formulas

of the

in

- mass in grams of 1 mole of a substance
- In other words . . . Add it all up!
1 mole of NaCl = 58g = 6.02x1023 particles of NaCl

1 mole of H2O = 18g = 6.02x1023 molecules of H20

- Use the gram formula mass and the gram atomic mass to determine
- how many moles or atoms of an element are found in some mass of a substance
- how much mass that element contributes to the mass of the entire substance
Use factor label & follow the units!

- If you have 1 molecule of (NH4)2SO4
- How many atoms of N are there?
- How many atoms of H?
SO…..

- If you have 1 mole of of (NH4)2SO4
- How many moles of N are there?
- How many moles of H?

PracticeRemember . . .1 mole = 6.02x1023atoms or molecules =______ gfm from the pt

Gases ONLY

@STP

- 1 mole of ANYgas
O2 (g)

NH3 (g)

He (g)

contains 6.02 x 1023 molecules and

occupies a volume of 22.4L

- STP
standardtemperature & pressure

0oC or 273K

101.3kPa or 1 atm

- Gases also have mass
1 mole of O2(g) = 32g

1 mole of NH3(g) = 17g

we can calculate Density!

- A sample of oxygen contains 3 moles of particles at STP what is its density?
- 2 steps
- Convert moles to mass AND volume
- Calculate density

- If mass or volume is given, use it and convert the other……. THEN calculate D!

Remember . . .

1 mole = 6.02x1023atoms or molecules =gfm = 22.4L (g)

“it’s a simple matter

of weight ratios . . .”

- The study of quantitative relationships that can be derived from chemical equations.

- If you look at chemical equations as recipes it may be easier to understand that
- changing the amount of a reactant will change the amount of the product IN THE SAME RATIO!

6CO2 + 12 H2O + 2804kJ 6O2 + C6H12O6 +6H20

Balanced equations

- Law of conservation of mass / matter
- ATOMS are not createdor destroyed during a chemical reaction, they are only rearranged to form new substances.
- # atoms on reactant side = # atoms on product side

- Law of conservation of E
- E on the reactant side = E on the product side

Practice

The End