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Sep 14 2013 06:25pm
all help is appreciated



) Molecule X is nonpolar. Molecule Y is polar. Both have approximately the same mass.
One is a liquid and one is a gas. Which is which. Explain your reasoning.

5) Molecule X has a molar mass of 150 g/mole. Molecule Y has a mass of 1200 g/mole.
Both are nonpolar liquids at room temperature. Which probably has the higher boiling point. Explain your reasoning.

6) Molecule X is a long unbranched hydrocarbon. Molecule Y is a highly branched isomer of molecule X that is
nearly spherical. Both are liquids at room temperature.
Which probably has the higher boiling point. Explain your reasoning.

7) The molar volumes of chlorine, bromine and iodine are given below.
Cl2
22.06 L/mole
Br2
0.0512 L/mole
I2
0.0515 L/mole
a)
Compute the density (g/cm3) of each substance.
b)
Account for the similarities and differences
between the substances in terms of
intermolecular forces.
8) Arrange the following substances
in order of increasing boiling point:
CH3
OH CH4
CF4
H2
O
Describe the nature of the intermolecular force for each substance
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Joined: Jan 23 2007
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Sep 16 2013 12:03am
Quote (tidus_ffx2 @ Sep 14 2013 06:25pm)
all help is appreciated



) Molecule X is nonpolar. Molecule Y is polar. Both have approximately the same mass.
One is a liquid and one is a gas. Which is which. Explain your reasoning.
Y would be a liquid due to dipole interactions being stronger than Van der Waal for example methane vs water

5) Molecule X has a molar mass of 150 g/mole. Molecule Y has a mass of 1200 g/mole.
Both are nonpolar liquids at room temperature. Which probably has the higher boiling point. Explain your reasoning.
Y because of increased Van der Waal forces

6) Molecule X is a long unbranched hydrocarbon. Molecule Y is a highly branched isomer of molecule X that is
nearly spherical. Both are liquids at room temperature.
Which probably has the higher boiling point. Explain your reasoning.
The linear chain has a higher boiling point because the molecules can stick closer together whereas the branched molecules have steric hindrance look at n-octane vs iso octane

7) The molar volumes of chlorine, bromine and iodine are given below.
Cl2
22.06 L/mole
Br2
0.0512 L/mole
I2
0.0515 L/mole
a)
Compute the density (g/cm3) of each substance.
1L=1000cm^3 so use the periodic table to get the molar mass. (molar mass / molar volume) divide that by 1000 to get g/cm^3
b)
Account for the similarities and differences
between the substances in terms of
intermolecular forces.
8) Arrange the following substances
in order of increasing boiling point:
CH3
OH CH4
CF4
H2
O
Describe the nature of the intermolecular force for each substance


For 8 do you mean O2? If you are having problems with this you should just change majors you won't survive.

Member
Posts: 8,405
Joined: Apr 2 2006
Gold: 285.01
Sep 17 2013 07:19pm
Quote (nobrow @ Sep 16 2013 01:03am)
For 8 do you mean O2? If you are having problems with this you should just change majors you won't survive.


Yes the last one is 02. If ny.major was chem I would think about switching. I've gone through 9 physics classes, and up through diff eqs and calc 3 without too much trouble. But when it comes to chem, I'm a dud
Member
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Sep 18 2013 04:50pm
Quote (tidus_ffx2 @ Sep 17 2013 09:19pm)
Yes the last one is 02. If ny.major was chem I would think about switching. I've gone through 9 physics classes, and up through diff eqs and calc 3 without too much trouble. But when it comes to chem, I'm a dud


Yeah but actual engineers never, ever, ever need to know this stuff ever never so don't worry (unless you're a chemical engineer)
Member
Posts: 8,405
Joined: Apr 2 2006
Gold: 285.01
Sep 18 2013 05:21pm
Quote (Alexander the Great @ Sep 18 2013 05:50pm)
Yeah but actual engineers never, ever, ever need to know this stuff ever never so don't worry (unless you're a chemical engineer)



Exactly. This is the 2nd of two chemistry classes i have to take. I will never use this crap again
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