U7D3Polyatomic Ions and GFM

U7D3: Polyatomic Ions and GFMHW: HW #3

Do Now: 1.HW out for check; LAB DUE

2. What is the charge on Pb in Pb3N2 ?

How do you know?

Name it.

What noble gas does the Nitrogen ion match?

Today: • Review/Quiz• Forming and Naming Ionic Compounds w/Polyatomic ions• GFM• TTL

IX. POLYATOMIC IONS (PAI)• A. Reference Table E• Groups of atoms bond

together by sharing electrons to form ions.

• one of the atoms in the group brings along a charge and group of atoms is not neutral

• “many atom” ion.

Complete this chart using reference table E.

carbonate

acetate

sulfate

chlorate

hydroxide

NO3 -

ClO2 -

CrO4 -2

SO3 -2

PO4 -3

• What type of charge do most of the PAI have? __________________

• Most of these PAI end in _________ or __________

• Two important exceptions are the positive ion

_________ (ammonium) and the negative ion

_________ (hydroxide).

negative

-ate -ite

NH4 +

OH-

B. Writing and Naming Compounds with Polyatomic Ions

Rules:• The formula must be in lowest terms• the charges must add up to zero. • Parenthesis are used around the polyatomic ion when more

than one of these ions is necessary in a formula: (NH4)2O.

• To name compounds with polyatomic ions, use the name of the polyatomic ion listed on the reference table.

• Ex: (NH4)2O is ammonium oxide;

• K2CO3 is potassium carbonate.

• ternary ionic compounds: K2CO3 and NaClO4

• binary ionic compounds: K2O and NaCl

Try your hand at these!

KNO3

Al(ClO3)3

SrSO4

KNO2

Mg3(PO4)2

Potassium nitrate

Aluminum chlorate

Strontium sulfate

Potassium nitrite

Magnesium phosphate

Going Backwards! ternary compounds

Na +1

Ca +1

K +1

Au +3

NH3 +

OH -

SO4 -2

CrO4 -2

CO3 -2

ClO4 -

NaOH

CaSO4

K2CrO4

Au2(CO3)3

NH3ClO4

Ok…so how’re we doing so far?

• So.. Fist to Five

Fist (not understanding need help)

Five (feel I can teach it)

•Show me where you stand

Stoichiometry of Formulas

• Stoichiometry means math relationship, in this case chemical formulas.

A. The Smartie Molecule

a) The smartie candy roll represents a molecule. The different colors represent different elements contained in the smartie molecule.

List the colors contained in your molecule:_____________________________________

(This is Qualitative data-> type of elements)

Smartie Datab) Color and number present in your “molecule” in “ROYGBIVW” order.

__________________________________________________

(This is Quantitative data-> type and number)

 

c) Identify the following statements as examples of quantitative or qualitative data.• ____The compound contains hydrogen and carbon atoms.• ____The compound contains 8 hydrogen and 4 carbon atoms.

B. The MOLEa) Write the formula of your smartie

molecule “ROYGBIV” (ex. R3O4....)

_______________

b) How many total “atoms” are present in

ONE smartie molecule? _____________

c) Molecules are too small a unit to count => new unit mole = 6.02 x 1023 items

one mole of molecules = 6.02 x 1023 molecules, etc.

1 mole of smartie molecules =____________ smartie molecules.

1 mole of atoms =6.02 x 1023 atoms1 mole of protons =6.02 x 1023 protons1 mole of Na+1 =6.02 x 1023 Na+1

6.02 x 1023

15

But… what of you have more than one mole?????

•Molteply!!!!2 moles of smartie molecules =

2 x (6.02 x 1023) = 1.20 x 1024molecules.

Counting moles (1,2,3 etc) is so much easier than counting molecules (multiples of 6.02 x 1023)

Since one smartie molecule contains ____“atoms”,

We say that one mole of smartie molecules

contain ______ moles of atoms.

15

15

Yuck!

d) Counting moles of atoms in a formula

Determine the number of moles of each element and the total number of moles of atoms present in one mole of the compound

ex.: KBr: 1 mole K & 1 mole Br ;

total moles of atoms = 2 moles

Li2O: 2 moles Li & 1 mole O ;

total moles of atoms = 3 moles

What about parentheses?

Multiply the number of each element inside the parenthesis by number on the outside the parenthesis:

Sr(NO3)2

Sr:1 mole; N: 2x1= 2 moles; O: 3x2=6 moles

total moles of atoms = 1 mole + 2 moles + 6 moles

total moles of atoms = 9 moles

Complete the table

1 mole Na

1 mole Cl

1 mole Ca 2 moles Cl

2 moles K1 mole S

4 moles O

1 mole Al

3 mole N

9 moles O

3 mole Mg

2 mole P

8 moles O

2 moles

3 moles

7 moles

13 moles

13 moles

C. How do you measure moles?

•with a BALANCE!!!!!

a. One mole of an element is equal to the atomic mass of that element in grams.

gram formula mass (GFM).

GFM: Gram Formula Mass• Look up the atomic mass of the element, round to the tenths place. unit: grams per mole (g/mole)Example: chlorine: Cl 35.5 g/mole. Remember: The unit for atomic mass on the PT for atoms is amu. For a mole…the unit is gram. Ex. The atomic mass of C is 12.0 amu so 1 mole of C will have a mass of 12.0 g.

In other words 12.0 g/mole

Determine the gram formula mass of the elements given (Don’t forget the units):

1.0 g/ mole

63.5 g/ mole 79.9 g/ mole

14.0 g/ mole

40.1 g/ mole

55.8 g/ mole 24.3 g/ mole

32.1 g/ mole

16.0 g/ mole

27.0 g/ mole

b. Gram Formula Mass of CompoundsGFM of a compound is the sum of the GFM of the elements of the atoms in the compound.

KBr K = 39.1 g/mole;

Br =79.9 g/mole

GFM= (39.1 + 79.9)g/mole

GFM =119.0 g/mole

Li2O Li = 6.9 g/mole;

O = 16.0 g/mole

Since there are 2 Li, you must multiply the GFM of Li by 2:

GFM = [2(6.9) + 16.0]

GFM = 29.8 g/mole

Sr(NO3)2 Sr = 87.6 g/mole; N = 14.0 g/mole; O = 16.0 g/mole

Again, you must multiply individual GFM by the number of each element present.

GFM = [87.6 + 2(14.0) + 6(16.0)] g/mole GFM = 211.6 g/mole.

Remember to show units & work! Units are g/ mole. NO Work NO CREDIT!!!!

Na + ClGFM= [23.0 + 35.5] g/mol

GFM = 58.5 g/mol

Na + O +HGFM=[23.0 + 16.0 +1.0] g/mol

GFM = 40.0 g/mol

Al + 3 FGFM= [27.0 + 3(19.0)] g/mol

GFM = 84.0 g/mol

Zn + S + OGFM=[65.4 + 32.1+16.0]g/mol

GFM = 161.5 g/mol

C. Special Formulas: Hydrates

Hydrates are ionic compounds that have certain number of moles of water trapped in the crystal structure of 1 mole of the hydrate.

Gypsum drywall used in the

construction of homes is a hydrate

of calcium sulfate.

The trapped water in the drywall

adds to the fire protection provided

by walls constructed of drywall.

The formula of gypsum drywall is CaSO42H2O.

The ”” means it’s a hydrate; NOT multiply !

Two moles of water are trapped for every one mole of CaSO4.

So..

GFM of CaSO42H2O

GFM of CaSO4 + 2 x GFM of H2O

GFM CaSO42H2O =

[40.1 +32.1+ 4(16.0)]g/mole + 2 [2(1.0)+16.0] g/mole

GFM = 172.2 g/mole

What is the GFM of CoCl26H2O ?• GFM of CoCl26H2O = GFM CoCl2+ 6 x GFM H2O

• Since the GFM of H2O is 18.0 g/mole, you can substitute that value in rather than calculate it each time.

• GFM = [58.9 + 2(35.5)] g/mole + 6 (18.0g/mole) • GFM = 237.9 g/mole• Remember:• Since there are 6 moles of water trapped in the CoCl26H2O, the GFM of water is multiplied by 6.

Remember to show units & work! NO Work NO CREDIT!!!!

Ticket to leave1. List a concept/skill that you mastered today.

2. List a topic/skill that you need to practice more

3. What do you still need help on?