ntermolecular Forces and Properties of Substances

Answer all the right answers to the questions.

Intermolecular Forces and Properties of SubstancesObjectives

This lab has two parts. In successfully completing this lab you will:

Don't use plagiarized sources. Get Your Custom Essay on
ntermolecular Forces and Properties of Substances
Just from $10/Page
Order Essay
  1. Review polarity of molecules using a PhET simulation, and predict how polarity will determine the types of intermolecular forces and properties of atoms/molecules. 
  2. Investigate the different intermolecular forces, and how microscopic properties affect the macroscopic behavior of substances.

Introduction

Understanding the properties of substances is crucial to designing laboratory experiments. Many properties of liquids and solids are affected by the intermolecular forces experienced by these substances. The type and strength of the intermolecular forces a molecule will experience is largely related to the polarity of the molecule. For lab this week we review polarity, and explore intermolecular forces. We will also investigate how intermolecular forces affect various properties of substances.Experiment Part 1: Polarity and Intermolecular Forces

Using the PhET simulation “Molecule Polarity”.

Adapted from “Intermolecular Forces and Molecules” by Ted Clark and Julia Chamberlain. (CC by 4.0) Link to original file here.

  1. At the bottom of the screen, choose Three Atoms.
  2. Under View, click the boxes so that Bond Dipoles, Molecular Dipole, and Partial Charges are all showing.
  3. Atoms A and C should have the electronegativity all the way to the left (less), and Atom B should have the electronegativity in the middle.
  4. Answer the following questions:
    1. What is the molecular shape of the molecule shown?
  1. Which atom(s) is more electronegative?
  1. Which atom(s) has the partial negative charge(s)?
  1. Which atom(s) has the partial positive charge(s)?
  1. Where do the bond dipoles point?
  1. Where does the molecular dipole point?
  1. How is the molecular dipole related to the bond dipoles?
Answer all the right answers to the questions. 1
  1. How is the electrostatic potential (charge distribution) of CO2 different than H2?
  2. Do these results support your predictions?
  3. What would predict the electrostatic potential to look like for SO2? Would it have positive and negative regions? Where would these be?
  4. Identify the molecules that would exhibit H-bonding in the following examples. What do you notice about the electrostatic potential of those molecules compared to those that do not exhibit H-Bonding?
Answer all the right answers to the questions. 2
  1. What types of IMFs would you expect Ne, Ar and O2 to have? Why?
  1. The following picture was taken from a different PhET simulation on states of matter. Which substance has the weakest intermolecular force? Explain your reasoning.
Answer all the right answers to the questions. 3
  1. Explain the differences in boiling points for the following molecules:
Answer all the right answers to the questions. 4

Part 2: Intermolecular Forces and Properties

Polarity affects the type and strength of intermolecular forces a substance will experience. In turn, the strength of intermolecular forces affect some properties of the substance. We will now investigate this further by looking at the different types of intermolecular forces, various substances, and their properties. Please use the data provided to answer the questions. Then, use your observations to make predictions about properties of substances.

Intermolecular Forces and Evaporation

In order for molecules to evaporate from the surface of a liquid, they must have enough kinetic energy (obtained from collisions with neighboring molecules) to break the attractions (intermolecular forces) they have for their neighbors. When the molecules escape from the gas phase, they carry this kinetic energy away with them. Therefore, evaporation is an endothermic process that cools the remaining liquid.

Figure 1: Evaporation of liquid particles.

Answer all the right answers to the questions. 5

Molecules that are not very sticky (i.e. those that have small intermolecular forces) can evaporate rapidly, causing the temperature of the liquid to drop quickly. Conversely, molecules with strong intermolecular forces will not experience much evaporation and little cooling will be observed. 

The change in temperature during a two minute evaporation period was recorded for several substances and organized in the table below. Use the following data to answer the next few questions:

Table 1: Change in Temperature During Evaporation and Total Number of Electrons in Various Hydrocarbons.

CompoundChange in T during evaporation (0C)Total number of electrons in compound
decane (C10H22)-1.482
nonane (C9H20)-2.874
octane (C8H18)-5.166
heptane (C7H16)-9.558
hexane (C6H14)-14.550
pentane (C5H12)-22.042

1. The compound with the strongest intermolecular forces is ________. The compound with the weakest intermolecular forces is ________. 

2. All of these compounds are polar/nonpolar (circle one). The predominant intermolecular force found in these substances is ________.

3. Based on the data above, the more/less electrons a substance has, the stronger the __________.

Compare two liquids: acetone (C3H6O) and 2-butanone (C4H8O). 

4. Of the two liquids above, ________ would have the stronger intermolecular forces.

5. Of the two liquids above, ________ would show the greater change in temperature during evaporation in a two minute time period.

Intermolecular Forces and Boiling Point

The boiling point is the temperature at which the liquid and gas exist in equilibrium. At this temperature the liquid molecules have gained enough energy to overcome the attractive intermolecular forces and escape into the gas phase. Also at this temperature, the gas molecules have lost enough energy to succumb to the intermolecular attractive forces and condense into the liquid phase. Use the following table to answer the questions below:

Table 2: Structures, Molecular Weight and Boiling Points of Several Substances. 

CompoundStructureMolecular Weight (g/mol)Boiling Point (0C)
pentane7236
1-butanol74118
2-butanone7280

1. Pentane is a polar/nonpolar molecule. The predominant intermolecular force in pentane is LDF/D-D/H-Bonding. (Circle one)

2. 1-butanol is a polar/nonpolar molecule. The predominant intermolecular force in 1-butanol is LDF/D-D/H-Bonding. (Circle one)

3. 2-butanone is a polar/nonpolar molecule. The predominant intermolecular force in 2-butanone is LDF/D-D/H-Bonding. (Circle one)

4. Rank the three principle intermolecular forces in order of weakest to strongest.

5. The stronger the intermolecular force, the lower/higher the boiling point. (Circle one)

6. Pentane, 1-butanol and 2-butanone share an intermolecular force that is approximately the same strength for all three compounds. What is the intermolecular force, and why is it approximately the same strength for all three compounds. Explain.


7. Draw Lewis Structures for acetone (C3H6O), butane (C4H10) and isopropanol (C3H8O) and determine the predominant intermolecular force in each compound. Use the structures to predict the boiling points given the data below:

CompoundBoiling Point (0C)
-1.0
56.0
82.5

Please show all work below.

8. Explain your answers for Question 7. Why did you place each compound where you did?

9. Draw Lewis Structures of the following compounds and determine their predominant intermolecular forces:

1. ethane (C2H6)

2. ethylene glycol (CH2OHCH2OH)

3. propane (C3H8)

4. ethanol (CH3CH2OH)

5. dimethyl ether (CH3-O-CH3)

Use the structures to predict the boiling points given the data below:

CompoundBoiling Point (0C)
-89
-42
-24
78
197

Please show all work on next page.

Lewis Structures for Question 9:

10. Explain your answers for Question 9. Why did you place each compound where you did? 

Order a unique copy of this paper
(550 words)

Approximate price: $22

Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

We value our customers and so we ensure that what we do is 100% original..
With us you are guaranteed of quality work done by our qualified experts.Your information and everything that you do with us is kept completely confidential.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

The Product ordered is guaranteed to be original. Orders are checked by the most advanced anti-plagiarism software in the market to assure that the Product is 100% original. The Company has a zero tolerance policy for plagiarism.

Read more

Free-revision policy

The Free Revision policy is a courtesy service that the Company provides to help ensure Customer’s total satisfaction with the completed Order. To receive free revision the Company requires that the Customer provide the request within fourteen (14) days from the first completion date and within a period of thirty (30) days for dissertations.

Read more

Privacy policy

The Company is committed to protect the privacy of the Customer and it will never resell or share any of Customer’s personal information, including credit card data, with any third party. All the online transactions are processed through the secure and reliable online payment systems.

Read more

Fair-cooperation guarantee

By placing an order with us, you agree to the service we provide. We will endear to do all that it takes to deliver a comprehensive paper as per your requirements. We also count on your cooperation to ensure that we deliver on this mandate.

Read more

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
$26
The price is based on these factors:
Academic level
Number of pages
Urgency
Open chat
1
You can contact our live agent via WhatsApp! Via +1 817 953 0426

Feel free to ask questions, clarifications, or discounts available when placing an order.

Order your essay today and save 30% with the discount code STARS