Chapter 12 problems
What type of forces, intermolecular or
intramolecular…
• A) prevent ice cubes from adopting the shape
of the container?
• B) are overcome when the ice melts?
• C) are overcome when liquid water vaporizes?
• D) are overcome when gaseous water is
converted to hydrogen and oxygen?
When nitrogen gas is compressed to form liquid
nitrogen, it cools to a very low temperature
(around -200oC). Molecularly speaking, the
nitrogen gas molecules released a lot of
energy (as heat). Where did this energy come
from?
Which one will have a higher vapor pressure:
a) ethanol or ethane?
b) 10mL H2O in a 3-cm diameter vial or 10mL
H2O in a 10-cm diameter culture plate?
At which condition will a wet rag dry faster?
a) 20oC or 40oC
b) 33% humidity or 10% humidity
Which one will have a higher melting point?
a) cis-fat vs trans-fat
b) CCl4 vs NaCl
• The exceptionally high heat capacity of water
is due to the number of H-bonding a single
water molecule have. How many can it have?
Show them.
• Calculate the total heat needed to convert
22.00 g of ice at -6.00oC to liquid water at
0.500oC.
• Given data: ΔHfus = 6.02 kJ/mol
• Cice = 2.09 J/g-oC
If a liquid has a ΔHvap of 35.5 kJ/mol, and a
boiling point of 122oC, what is its vapor
pressure at 113oC?
Consider the phase diagram…
·E
·
B
·
·A
·
C
·D
F