Chemistry SM-1131Week 5 Lesson 1

Dr. Jesse ReichAssistant Professor of Chemistry

Massachusetts Maritime AcademyFall 2008

Class Today• Quote• Test Returned• Test Review• Molecules, Compounds, Nomenclature• No Class on Friday, but you’ll have to make one up

later

Quote

• “To be successful in college you have to learn to work hard and play hard.”

-Justin Reich

What does that mean?

• Don’t do homework with friends in your room.• Don’t hang with friends when you have to do

work.• Don’t think about work when you are chilling

with friends.• If you got less than a raw 70 you really have to

do the homework or risk failing this course• You won’t pass this class just listening

Test• 1A- 3,4,6,1,5• 1B- 2.25e2, 4.343e3, 4.34300e3, 2e4, 2.0000e4• 2- 3,2,4• 3-more, 82.5mL * 1.3255 g = 109.35g = 109g mL• 4- 1,000mL, 4.322L, 2.0 yards• 5- Reactants -> Products

Test

• 6- q = m*C*DT= 235g*75C*4.18J/gC= 73672.5J = 7.4e4J

• 7- Nucleus, proton• 8- isotope, ion, halogen• 9- JJ Thompson• 10- check out your notes

Compounds

• Joseph Proust- 1754-1826• Law of Constant Composition: All samples of a

given compound have the same proportions of their constituent elements

• Every molecule of water has H2O, every molecule of sugar is C6H12O6

What’s it mean

.

H is the symbol O is the symbol

2 is how many Hs there are

How many Os?

More complicated…

• Mg(NO3)2

• There is one Mg• There are 2 groups of (NO3)

• In each NO3 there is 1 N and 3 O

• The math 2 * 1N = 2N • The math 2 * 3O = 6O• Total formula= Mg1N2O6

Atomic Elements

• Noble Gases, many metals exist simply as just their element

Molecular Elements

• Many elements are not stable enough to exist on their own without forming molecules:

• H = H2, N = N2, O = O2, F = F2, S = S8, Cl = Cl2,

• Br = Br2, I = I2

• These are so unstable they need to form molecules to exist, they are molecular elements

2 Compound Types

• Ionic Compounds: Are between two or more ions, most of them are between a metal and a non-metal

• Molecular Compounds: Are between 2 or more non-metals

Compound TypesIonic: Metal and a non-metalMolecular: 2 non metals

Memorize this Table

• Group 1= +1• Group2= +2• Group13= +3• Group14= + or – 4• Group 15= -3• Group 16 = -2• Group 17= -1• Group 18 = No Charge Ever!

Ionic Compounds

• They are overall neutral, but each component has a charge. So, we have to make sure that charges are balanced.

Ionic Compound Making

• 1- Write their symbols• 2- Write their charges to the upper right• 3-Switcheroo• 4- (Reduce)• MEMORIZE THIS!

Ionic Compound Example 1

• Magnesium and Chlorine form a compound what is the formula?

• MgCl• Mg+2Cl-1

• Mg1Cl2 l can also write this as MgCl2

• 1:2 does not reduce

Ionic Compound Example 2

• Aluminum and Chlorine form a compound what is the formula?

• AlCl• Al+3Cl-1

• Al1Cl3 l can also write this as AlCl3

• 1:3 does not reduce

Ionic Compound Example 3

• Aluminum and Oxygen form a compound what is the formula?

• AlO• Al+3O-2

• Al3O2

• 3:2 does not reduce

Ionic Compound Example 4

• Magnesium and Oxygen form a compound what is the formula?

• MgO• Mg+2O-2

• Mg2O2

• 2:2 does reduce to 1:1• Mg1O1 or MgO

Ionic Compound Example 5

• Aluminum and Nitrogen form a compound what is the formula?

• AlN• Al+3N-3

• Al3N3

• 3:3 does reduce to 1:1• Al1N1 or AlN

Naming Ionic Compounds

• Hold UP!• Ionic Compounds have 1 naming system• Molecular compounds have a 2nd naming

system that works differently• Ionic Compounds are between metals and

non-metals

Naming Metals

• Alkali, alkaline earth, and group 3 metals are easy to name in compounds when saying their names out loud. Just use what you see on the periodic table.

• Al is aluminum, Na is sodium, Mg is Magnesium

Transition Metals

• Alkali metals are easy. The charge is always 1. Alkaline earth metals are easy the charge is always 2. Group 13 metals are easy the charge is always +3.

• Transition metals, lanthanides, actinides, and all the other metals are trickier. There are multiple charges they can have and multiple names for the metals depending on their charge.

T.M. Example

• Iron can exist in stable forms with a +2 or +3 charge. We write the symbol as as Fe+2 and Fe+3 or Fe(II) and Fe(III) or Iron (II) and Iron (III)

• Copper typically has a +1 or +2 charge. We will write it as Cu+1 or Cu+2e or Cu(I) and Cu (II) or Copper (I) and Copper (II)

Transition Metals

• Chemistry is old. We’ve actually gone through 2 naming systems for transition metals.

• The old system had certain names for certain charges. Fe+2 and Fe+3 were called ferrous and ferric. We won’t use those names in here, but you should at least read the list and be familiar.

Naming Ionic Compounds

• The non-metal in ionic compounds gets it’s name changed.

• Chlorine becomes chloride• Oxygen becomes oxide• Nitrogen becomes nitride• Fluorine becomes Fluoride• Sulfur becomes Sulfide• Iodine becomes Iodide

All the way through

• Magnesium and Nitrogen form a compound what is it’s formula and name?

• MgN• Mg+2N-3

• Mg3N2

• Can’t reduce• Magnesium Nitride

What about Iron (II) and Nitrogen

• Fe and N• Fe+2 and N-3

• Fe3N2

• 3:2 doesn’t reduce• Iron (II) Nitride

It’s a lot to learn

• You won’t learn it all in class• If you got less than a 70 raw score do the

homework think of it as mandatory• This class will get harder not easier• Stop screwing around with your friends as

much. You’re not paying 15k and taxpayers aren’t helping with an additional 15k just so you can screw around. Get to work.