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My report on "Intermolecular Attractions"
My report on "Intermolecular Attractions"
Student name: Katie McClain
Teacher name: rtaylor
School: The Hockaday School
Submission Time: 5/1/09 3:14 PM
Page 1 : http://mw2.concord.org/public/part2/vdw/page1.cml
1. What is the difference between polar and non-polar molecules? (Be sure to include more than the colors used to represent them in your response!)
Non-polar molecules have evenly shared electrons. Polar molecules have an uneven sharing of electrons, causing the formation of a partial positive and partial negative ends. (2:53:22 PM)
2. Image showing intermolecular attractions:
(2:54:36 PM)
3. Which of the following formed intermolecular attractions (check all that apply):
(a) + ends of polar molecules to + ends of other polar molecules
(b) + ends of polar molecules to - ends of other polar molecules
(c) - ends of polar molecules to - ends of other polar molecules
(d) non-polar molecules to other non-polar molecules
(e) non-polar molecules to + parts of polar molecules
(f) non-polar molecules to - parts of polar molecules
My answer is (b) (d) (e) (f) (2:54:51 PM)
Page 2 : http://mw2.concord.org/public/part2/vdw/page2.cml
1. What is the primary attraction between NON-POLAR molecules:
(a) London Dispersion attraction
(b) dipole-dipole attraction
(c) gravitational attraction
(d) magnetic attraction
My answer is (a) (2:55:38 PM)
2. What is the primary attraction between POLAR molecules:
(a) London Dispersion attraction
(b) dipole-dipole attraction
(c) gravitational attraction
(d) magnetic attraction
My answer is (b) (2:55:40 PM)
3. Which type of intermolecular attraction is strongest:
(a) London Dispersion attraction
(b) dipole-dipole attraction
(c) gravitational attraction
(d) magnetic attraction
My answer is (b) (2:55:44 PM)
Page 3 : http://mw2.concord.org/public/part2/vdw/page3.cml
1. Which liquid boiled first (i.e. had the lowest boiling point):
(a) The polar liquid boiled first.
(b) The non-polar liquid boiled first.
(c) They both boiled at the same time.
My answer is (b) (2:56:22 PM)
2. Explain how intermolecular attractions affect the boilng point of a substance.
The greater the intermolecular attraction the higher the boiling point because it takes much more heat to break up a stronger molecule. (2:57:06 PM)
3. Explain why polar and non-polar substances won't stay mixed with each other.
Like disolves like. The strengths of their intermolecular forces are different. (2:57:56 PM)
Page 4 : http://mw2.concord.org/public/part2/vdw/page4.cml
1. Which molecule had the strongest attraction:
(a) the least polar molecule
(b) the medium polarity molecule
(c) the most polar molecule
My answer is (c) (2:58:23 PM)
2. Explain why polarity has an affect on the strength of attraction between molecules.
The most polar molecule will have the most london dispersion and dipole diple strength because it needs more strength to hold it together. (2:59:24 PM)
3. Which substance will have the highest boiling point:
(a) 1-heptanol
(b) 1,7-heptanediol
(c) 1,4,7-heptanetriol
My answer is (c) (2:59:24 PM)
4. Explain your choice for highest boiling point:
It has the largest surface area, thus the most strength, thus the highest boiling point to break apart the intermolecular attraction.. (3:00:11 PM)
Page 5 : http://mw2.concord.org/public/part2/vdw/page5.cml
1. Which molecule pairs had the strongest attraction (check all that apply):
(a) the two small molecules
(b) the two large straight molecules
(c) the large straight and bent molecules
(d) the large straight and circular molecules
(e) the large curved and circular molecules
My answer is (b) (e) (3:01:43 PM)
2. Propane boils at -42°C, butane at 0°C, and pentane at 36°C. They are all straight molecules. Which one is the biggest?
(a) propane
(b) butane
(c) pentane
My answer is (c) (3:01:57 PM)
3. Small molecules did not attract well. However, only some of the large ones had a strong attraction. Describe how both size and shape play a role in the strength of the London Dispersion attraction.
More surface area has more places to attract thus more strength. (3:02:29 PM)
Page 6 : http://mw2.concord.org/public/part2/vdw/page6.cml
1. Snapshot with annotations indicating hydrogen bonds:
(3:03:39 PM)
2. While not possible, imagine that water molecules had no attraction for each other at all. Would you most likely find water as a solid, liquid, or gas? Explain your reasoning.
As a gas because the molecules would not want to bind together so as a gas they could move freely unattached and bonded to one another. (3:04:23 PM)
Page 7 : http://mw2.concord.org/public/part2/vdw/page7.cml
1. Which pair of bases is held together more strongly: C and G, or A and T? How do you know?
The C and G because it has 3 bonds where A and T only has two bonds. (3:06:16 PM)
Page 8 : http://mw2.concord.org/public/part2/vdw/page8.cml
1. Image of the 3D anitibody/antigen from top of page:
(3:07:32 PM)
2. Image of the anitbody you just designed:
(3:09:44 PM)
Page 9 : http://mw2.concord.org/public/part2/vdw/page9.cml
1. Why do you think a gecko's feet stick much better to a wall than your fingers? Think about surface area, intermolecular attractions, and the rough surface (on a microscopic level) of a typical wall.
A gecko's feet are covered with millions of tiny hair so a lot more surface area and a lot more attraction to the rough surface of a typical wall. (3:11:48 PM)
Page 10 : http://mw2.concord.org/public/part2/vdw/page10.cml
1. Which of the following is NOT an attractive force between molecules:
(a) London dispersion
(b) dipole-dipole
(c) covalent bond
(d) hydrogen bond
My answer is (c) (3:12:07 PM)
2. Which factors affect the strength of the intermolecular attractions? (check all that apply)
(a) the color of the molecules
(b) the polarity of the molecules
(c) the shape of the molecules
(d) the size of the molecules
My answer is (b) (c) (d) (3:12:15 PM)
3. You have two substances: A and B. Both have molecules of similar size and shape. Substance A has molecules that attract with London dispersion attraction, and substance B has molecules that attract with dipole-dipole attraction. Which one will have the higher boiling point?
(a) Substance A
(b) Substance B
My answer is (b) (3:12:23 PM)
4. Explain why you chose Substance A or B.
Substance B because it is polar with dipole-dipole attraction meaning it has stronger intermolecular strength and has a higher boiling point. (3:13:30 PM)
5. You have two substances, both of which have the same boiling point (or attraction between their molecules). The first substance is made from molecules that are small (just a few atoms bonded together), and the second substance is made from molecules that are larger (many atoms bonded together). How can it be possible for two such different molecules to yield substances with the same boiling point? Describe the kinds of intermolecular attractions that must be involved and any other properties of the molecules that could cause this result.
The first molecules probably has hydrogen bonding which would add to a cause of this result (3:14:07 PM)
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