Questions (Clickers)
If you were interested in disrupting the noncovalent
interactions between water molecules in ice you could:
1
A)
Shine light on the ice.
B)
Stick the ice in a freezer.
C)
Hit the ice with a hammer.
D)
Add heat to the ice.
Questions (Clickers)
When heat is added to liquid propane, (CH3CH2CH3), it
warms until reaching the boiling point, and then changes into
a gas. Which of the following statements most accurately
describes what is going on:
2
A)
The added kinetic energy is causing the carbon and
hydrogen atoms in propane to separate from one another.
B)
The added kinetic energy is causing the disruption of both
hydrogen bonds and London dispersion forces between the
propane molecules.
C)
The added kinetic energy is causing the disruption of the
London dispersion forces between the propane molecules.
D)
The added kinetic energy is causing the propane to change
into methane gas.
Questions (Clickers)
When heat is added to liquid ethanol, (CH3CH2OH), it warms
until reaching the boiling point, and then changes into a gas.
Which of the following statements accurately describes what
is going on:
3
A)
The added kinetic energy is causing the carbon and
hydrogen atoms to separate from one another.
B)
The added kinetic energy is causing the disruption of both
hydrogen bonds and London dispersion forces between the
ethanol molecules.
C)
The added kinetic energy is causing the disruptions of the
London dispersion forces between the ethanol molecules.
D)
The added kinetic energy is causing the ethanol to change
into methane gas and water vapor.
Questions (Clickers)
Both propane (M = 44 g/mol) and ethanol (M = 46 g/mol)
have comparable molecular weights. Which do you predict
has the higher boiling point? Explain why.
4
A)
They should have similar boiling points.
B)
The ethanol should have the higher boiling point.
C)
The propane should have the higher boiling point.
D)
It is hard to tell without doing the experiment.
Questions (Clickers)
When the ice melts from the surface of a pond on a warm
spring day, this change is
5
A)
spontaneous
B)
nonspontaneous
Questions (Clickers)
When the ice forms on the surface of a pond on a cold winter
day, this change is
6
A)
spontaneous
B)
nonspontaneous
Questions (Clickers)
Before going on a picnic on a hot sumer day, you stopby the
store and pick up a block of dry ice, CO2(s).
In terms of ΔH alone, is the sublimation of dry ice
7
A)
Spontaneous
B)
Nonspontaneous
Questions (Clickers)
Before going on a picnic on a hot sumer day, you stopby the
store and pick up a block of dry ice, CO2(s).
In terms of ΔS alone, is the sublimation of dry ice
8
A)
Spontaneous
B)
Nonspontaneous
Questions (Clickers)
Before going on a picnic on a hot sumer day, you stopby the
store and pick up a block of dry ice, CO2(s).
At 50°C (This is one hot day!!) the ΔG for the sublimation of
dry ice as a
9
A)
negative value.
B)
positive value.
Questions (Clickers)
You planning to do some surgery on your kitchen table and
know that you need to sterilize your instruments by heating
them to 120°C. You rummage around in the kitchen
cupboards and find a pressure cooker that can heat water to
a pressure of 1.4 atm. Will this be sufficient for sterilizing your
instruments? (You may use Table 5.6 in your book to answer
this question; see the previous slide.)
A)
Yes
B)
No
Explain you answer.
10
Questions (Clicker)
Pentanoic acid and 1-pentanol have the same number of
carbon atoms. Which one is expected to have the higher
solubility in water? Explain.
A)
O
Pentanoic acid
CH
CH2 CH2
B)3 CH
1 2Pentanol
C)
11
pentanoic
Neitheracid
C
OH
CH3 CH2 CH2 CH2 CH2 OH
1-pentanol