Transcript Monday, February 9th, 2015 - Kenwood Academy Chemistry

Monday, February 9th, 2015
Classroom expectations:
•
1.Wear Kenwood ID.
2.Cell phones, music
•
players, and headphones
are put away.
3.Food is disposed of or
•
put away.
4.Dressed appropriately. •
5.Notebook is out and you
are ready for today’s class. •
HW: Study for Quiz!
Objective 6: We will name covalent
compounds and draw Lewis Dot
Structures of covalent compounds.
Catalyst:
A. A technique of adding titrant to a
sample solution.
B. A substance showing the
conductivity of a solution.
• C. A substance changing color to
indicate a solution being neutral.
• D. There is not enough information
to determine.
Announcements
• Tutoring TODAY and THURSDAY after
school.
• Quiz TOMORROW!
Agenda
• Catalyst
• Organize Binders
• Naming and Lewis Dot Practice
Naming Molecular Compounds
• How do you name molecular compounds?
(Share your answers from #15)
– First Name: Name of element with a prefix ONLY IF
more than one
– Last Name: Name of element with a prefix
ALWAYS and an –ide ending
• Note: if a prefix ends in A or O and attached to the
element OXYGEN, the vowel on the prefix is dropped
– Ex: CO  Carbon Monoxide, NOT Carbon Monooxide
Prefixes from POGIL
•
•
•
•
•
•
•
•
•
•
1 = mono
2 = di
3 = tri
4 = tetra
5 = penta
6 = hexa
7 = hepta
8 = octa
9 = nona
10 = deca
Fill in on page 2 of
POGIL if you don’t
have it already
Naming Molecular Compounds
Examples
• BCl3
– Boron Trichloride
• NI3
– Nitrogen Triiodide
• ClF
– Chlorine Monoflouride
• P4O10
– Tetraphosphorus Decoxide
Practice
1) Name the following
compounds
a. PBr3
b. SCl4
c. N2F2
d. SO3
e. BrF
f. MgF2
2) Write the formula for
the following names
a. Disulfur decafluoride
b. Carbon tetrachloride
c. Oxygen difluoride
d. Dinitrogen trioxide
e. Tetraphosphorus
heptasulfide
f. Sodium Bromide
Answers
1) Name the following
compounds
a. Phosphorous
Tribromide
b. Sulfur Tetrachloride
c. Dinitrogen Difluoride
d. Sulfur Trioxide
e. Bromine Monofluoride
f. Magnesium Fluoride
(Ionic!!)
2) Write the formula for
the following names
a. S2F10
b. CCl4
c. OF2
d. N2O3
e. P4S7
f. NaBr (Ionic!!)
Tuesday, February 10th, 2015
Classroom expectations:
1.Wear Kenwood ID.
•
2.Cell phones, music
players, and headphones •
are put away.
3.Food is disposed of or
•
put away.
4.Dressed appropriately.
•
5.Notebook is out and you
are ready for today’s class.
HW: None!
Objective: We will discuss
intermolecular forces.
Catalyst:
Name and draw the Lewis Dot
structure for:
• PCl3
Thursday, February 12th, 2015
Classroom expectations:
1.Wear Kenwood ID.
•
2.Cell phones, music
players, and headphones •
are put away.
3.Food is disposed of or
•
put away.
4.Dressed appropriately.
•
5.Notebook is out and you
are ready for today’s class.
HW: (next slide)
Objective: We will discuss intra
and intermolecular forces.
Catalyst:
Think about Hydrogen
monobromide (HBr): Will
electrons spend an equal amount
of time around the hydrogen atom
as the bromine atom? Explain.
Homework Questions
• Are electrons equally or unequally
shared in a polar bond? Draw a picture to
support your answer.
• Are the compounds below ionic, polar
covalent, or non-polar covalent?
–A. HBr
b. H2O
c. CO
–D. NaBr
e. HI
f. H2
–G. Br2
h. CaO i. MgS
Announcements
• Lab starting Tuesday
–Lab Report Due the following Monday!
–NO LATE REPORTS ACCEPTED!!
• Test NEXT FRIDAY!!
Agenda
• Catalyst
• Polarity Notes
• Exit Skip/Homework
Table of Contents
Electronegativity
• The electronegativity value
• indicates the attraction of an atom for shared
electrons.
• increases from left to right going across a period on the
periodic table.
• is high for the nonmetals with fluorine as the highest.
• is low for the metals.
15
Some Electronegativity Values for Group
A Elements
Electronegativity` increases
Electronegativity decreases
High
values
`
Low
values
Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings
16
Nonpolar Covalent Bonds
A nonpolar covalent bond
• occurs between nonmetals.
• is an equal or almost equal sharing of electrons.
• has almost no electronegativity difference (0.0 to 0.4).
Examples:
Electronegativity
Atoms Difference
Type of Bond
N-N
3.0 - 3.0 = 0.0 Nonpolar covalent
Cl-Br 3.0 - 2.8 = 0.2 Nonpolar covalent
H-Si
2.1 - 1.8 = 0.3 Nonpolar covalent
17
Polar Covalent Bonds
A polar covalent bond
• occurs between nonmetal atoms.
• is an unequal sharing of electrons.
• has a moderate electronegativity difference (0.5 to 1.9).
Examples:
Electronegativity
Atoms Difference
O-Cl
3.5 - 3.0 = 0.5
Cl-C
3.0 - 2.5 = 0.5
O-S
3.5 - 2.5 = 1.0
Type of Bond
Polar covalent
Polar covalent
Polar covalent
18
Comparing Nonpolar and Polar Covalent
Bonds
Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings
19
Ionic Bonds
An ionic bond
• occurs between metal and nonmetal ions.
• is a result of electron transfer.
• has a large electronegativity difference (2.0 or more).
Examples:
Electronegativity
Atoms Difference
Type of Bond
Cl-K
3.0 – 0.8 = 2.2
Ionic
N-Na 3.0 – 0.9 = 2.1
Ionic
S-Cs
2.5 – 0.7 = 1.8
Ionic
20
Electronegativity and Bond Types
TABLE
4.14
21
Predicting Bond Types
22
Learning Check
For the covalent compounds below, draw
the Lewis Dot Structure, using the
geometry sheet to help with the shape.
Draw the arrow to show the partial
positive and partial negative end of the
molecule.
A.
B.
C.
D.
H—S
H—Br
H—C
H—Cl
23
Learning Check
Of the molecules you just drew, rank them
in order from most polar to least polar.
A.
B.
C.
D.
H—S
H—Br
H—C
H—Cl
24
Learning Check
Use the electronegativity difference to identify
the type of bond between the following:
nonpolar covalent (NP), polar covalent (P), or
ionic (I).
A.
B.
C.
D.
K-N
N-O
Cl-Cl
H-Cl
25
Solution
Use the electronegativity difference to identify
the type of bond between the following:
nonpolar covalent (NP), polar covalent (P), or
ionic (I).
A.
B.
C.
D.
K-N
N-O
Cl-Cl
H-Cl
2.2
0.5
0.0
0.9
ionic (I)
polar covalent (P)
nonpolar covalent (NP)
polar covalent (P)
26
Not only are bonds polar – but so are
molecules!
• What type of bonds form among atoms in a
water molecule?
• What forces hold water molecules together?
• How can an insect walk on water, but you
can’t?
27
Exit Ticket
• What are 3 things you learned today?
• What are 2 things you wonder?
• What is one question you have about forces
between atoms and among molecules?
Friday, February 13th, 2015
Classroom expectations:
1.Wear Kenwood ID.
•
2.Cell phones, music
players, and headphones •
are put away.
3.Food is disposed of or
•
put away.
4.Dressed appropriately.
•
5.Notebook is out and you
are ready for today’s class. •
HW: (next slide)
Objective: We will discuss intra
and intermolecular forces.
Catalyst:
Label the top of your paper with:
Intermolecular Forces Notes
• On the top of what will be your
notes for today:
• Why do people put salt in boiling
water to cook with?
Homework
• What is hydrogen bonding?
• What causes London Dispersion forces?
• Rank the following intermolecular forces
from weakest to strongest: dipole-dipole,
ionic forces, dispersion forces, hydrogen
bonds.
• Rank the following intramolecular forces
from weakest to strongest: ionic bonds,
polar covalent bonds, nonpolar covalent
bonds.
Homework Check
• Are electrons equally or unequally
shared in a polar bond?
• Electrons are shared unequally in polar
bonds and equally in nonpolar bonds.
• Are the compounds below ionic, polar
covalent, or non-polar covalent?
–A. HBr P b. H2O P
c. CO P
–D. NaBr I e. HI NP
f. H2 NP
–G. Br2 NP h. CaO I
i. MgS P
Announcements
• Lab starting Tuesday
–Lab Report Due the following Monday!
–NO LATE REPORTS ACCEPTED!!
• Test NEXT FRIDAY!!
Agenda
• Catalyst
• Intermolecular Notes
• Exit Slip/Homework
Table of Contents
Intra vs. Inter
• Internet: network shared between people
worldwide
– Inter: “between” or “among”
• Intranet: network shared between people in a
specific group. Example: CPS student portal
– Intra: “within”
Intramolecular Forces
• Forces within a molecule
– 2 types: covalent & ionic
What types of bonds are present within this H2O
molecule?
Intramolecular
Covalent
Intramolecular Forces
What types of bonds are present within NaCl?
Intramolecular Ionic
Na+
Cl-
Intramolecular Forces
Bond type
Element-Type
Ionic Bond
Metal - nonmetal
Covalent: Polar
Nonmetal - nonmetal
Bond
Strength
weak
strong
Covalent:
Nonpolar
Nonmetal - nonmetal
strongest
Intermolecular Forces
• Forces between molecules
• Much weaker than intramolecular forces
• Intermolecular forces are caused by the polarity
difference WITHIN a molecule
Intramolecular Force
Intermolecular Force
Intermolecular Forces: Inquiry
• 3 beakers containing different liquids will be
passed around the room. (Beaker A, B, and C)
• As the beakers are passed around waft the
beaker and note any differences in what you
smell.
– Note: DO NOT place nose directly into mouth of
beaker.
Intermolecular Forces: Inquiry
Beaker A
C3H6O
Beaker B
Beaker C
C3H7OH
H2O
•What did you notice about the liquids in the beakers?
•Why do you think this occurred?
•The difference in what you smelled were due to the
INTERMOLECULAR FORCES between the molecules in each
beaker.
Intermolecular Forces
• Influence the boiling point and melting point
of a substance. The stronger the force the
higher the melting and boiling point.
gas
liquid
*Break through intermolecular forces when going from
a liquid to a gas– NOT intramolecular!
Intermolecular Forces
• Based on your observations, which beaker
held the substance with the weakest
intermolecular forces?
Intermolecular Forces
• 4 different types of intermolecular forces
exist
– Ionic – attraction of + and - ions
Intermolecular Forces
– Hydrogen – attraction of H to very
electronegative atoms (O, F, N)
– Dipole-Dipole – attraction between partially
positive and partially negative ends of polar
molecules
– London Dispersion – attraction between
non-polar molecules because of dipole
moments
Ionic Intermolecular Forces
• Occur between ionic compounds
• Strongest attraction due to the positive and negative
ions
• Crystal lattice structure formed due to attraction
between molecules
• Examples: Na---Cl, K---Br, Ca---Cl
Intermolecular Forces
Intramolecular
Bond
Intermolecular
Force
Force Strength
Ionic
Ionic Force
strongest
Covalent: Polar
Hydrogen Bonding
weak
Covalent: Polar
Dipole-Dipole
weak
Covalent: Nonpolar
London Dispersion
weakest
Card Sort
• With your elbow partner, sort the cards as
described on the half sheet. Then, answer the
questions on the half sheet in your notes.
Distilled Water vs Salt Water
Distilled Water
• Forces present in distilled
water:
– Dipole-Dipole
– Hydrogen
Salt Water
• Forces present in salt water:
– Dipole-Dipole
– Hydrogen
– Ionic
Explain: Elbow Partner Discussion
• Sugar is a covalent compound and salt is an
ionic compound. Based on what you learned
today, why will sugar have a lower melting
point? Explain using the vocabulary from the
lesson.
Sucrose
NaCl
Answer the Critical Thinking
Questions
• In your notes, answer the critical thinking
questions on the back of the classwork half –
sheet.
Exit Ticket
Idk
1
2
3
4
Mastered
5
Answer the following questions:
1.) Rank the following intermolecular forces from
strongest to weakest: dispersion, hydrogen, ionic,
dipole-dipole
2.) What forces would be present in a container of
sugar water vs a glass of salt water? Based on these
forces, which container would evaporate first?