!!

Unit*3.*Mole*Unit*! Unit!conversions!involving!(HI!#4S7)*

o Atom,!molecule,!particle,!mole,!gram,!molarity,!density,!molar!mass,!volume,!gas!at!STP**

! Stoichiometry*

! !~ 15 classes 5 Quizzes (2 before break) 4 HIs 1 Formal Lab 1 Gum Lab 1 Unit Test

Chemistry 11 – Mole Concept Study Guide 1

Avogadro’s Number:

• There is a convenient unit when working with small particles such as atoms and molecules.

• This number is known as _________________, which is called __________________________, to honour the Italian scientist whose hypothesis led to its determination.

• If written out, this number looks like this:

602 000 000 000 000 000 000 000

Why do we need to know such a big number like this in Chemistry?

• Elements have different atomic masses (eg. Mg = 24.3g/mol, Ca = 40.1g/mol)

• Atoms and molecules are _____________ – we will work with _______ quantities of them.

• Need a convenient _____ to count atoms and molecules

• Example: A dozen ! instead of counting 1, 2, 3, we count by 12’s ! a known quantity that is understood by all. ! A convenient unit

• Chemists use a special term that is similar to “a dozen”.

• This term is called the “_________”

• 1 Mole is the same as having 6.02 x 1023 “things”

• Examples:

" 1 mole of Carbon atoms = 6.02 x 1023 Carbon atoms " 1 mole of Oranges = 6.02 x 1023 Oranges " 1 mole of Basketballs = 6.02 x 1023 Basketballs " 1 mole of Teachers = 6.02 x 1023 Teachers

• Notice in your comparisons that even though the ______ of a teacher is significantly

greater than the _______ of an orange, you will still get 6.02 x 1023 of them in a mole!

• Molar Mass: ___________________________________________________________.

" For an element, the molar mass is shown on the __________________________ " For a compound, it is the _____ of the atomic masses for each of the elements that

comprise it.

23

6. 02 X 10 Avogadro 's number

← to left 23 times

• y•

very small large

Unit" mole

"

moleuse mot as the unit w/ #

.

mass

mass

the mass of one mole of substance ( glmol )

periodic table eg ) carbon = 12.01

sum

Chemistry 11 – Mole Concept Study Guide 2

Molar Mass Calculation Notes

Step 1. Begin by separating out the different atoms found in the compound. H2O:

Step 2. Beside each atomic symbol, write how many are found in the compound. H2O: Step 3. Find the atomic mass of each atom and write the mass next to number corresponding to its element. H2O: Step 4. Multiply the atomic mass with the number of atoms of that element in the compound formula. H2O: Step 5. Add all totals to get the molar mass of the compound. H2O: Try these harder ones: (NH4)2SO4: Cu(NO3)2 • 6H2O:

Rule-

H When calculatingO

AutonsMM , Use IDP

.

H 2

O I

H 2 X 1.0 = 2 . O g

O I X 16.0 = 16.09

2. Og t 16.0g = 18.09

•

°

.MM ( Hz = 18.09 lmol

EIn Imol of H2O ,

you 'd weigh 18.0g .

→N 2 X 140 = 28.0

H 8 × 1- ° = & ° } SUM = 132. IpA m "

S 1 X 32.1 = 32- I

use IDP

O 4 X 16.0 = 64.0

6 6

If fun) copper # nitrate hexahydrateCU I x = 63.5

µ z ×

434.50= 28.0 } 295.591mm

O 12 X 16.0 = 192.0

H 12 × 1.0 = 12.0

Chemistry 11 – Mole Concept Study Guide 3

Diatomic Elements:

There are certain elements that exist as diatomic gas rather than single atom in nature. They are: Note:You must know these! To find molar mass of these gases, don’t forget to multiply the elemental molar mass by ___. Eg. Find the molar mass of hydrogen gas Molar Mass = Eg. Find the molar mass of chlorine gas Molar Mass =

HzIzBrzOzNzCkFz

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H22.091mm

Eg .Find the MM of Chlorine Ton

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Ck CI-

2X ( 35.5 )

= 71.091mg 35.59mmol

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