DISCOVERY EXERCISE – ORGANIC COMPOUNDS – What are they?
NAME______DATE______
Introduction:During this exercise, you and your group will be studying organic compounds. You will be building models, testing actual substances, and looking up information for four different organic compounds in order to do the following:
1)Look for molecular characteristics and properties that all organic compounds have in common and use that information todevelop a definition of what an organic compound is.
2)Organic compounds can be divided into two major groups. You also will attempt to place these four compounds into two groups and try to describe what properties each group has.
The compounds you will consider are: Methane CH4
Methanol CH3OH
Hexane C6H14
Trichloromethane CHCl3
Procedure & Observation Charts:
1)For each compound: A) list the elements found in it (see above) and B)identify each compound as ionic, covalent, or metallic.Group Plan – each person take one or two of these to figure out then share and discuss results.
------Elements------Ionic/Covalent/Metallic------
Methane
______
Methanol
______
Hexane
______
Trichloromethane
______
2)For each of the compounds that you have found is covalent: draw a dot structure, build the model, draw a 3-D sketch, give a shape name, determine if the molecule is polar, and determine the type of intermolecular bonding.Group Plan – each person should “be in charge” of a compound by building it & leading discussion of each item.
Compound dot structure 3-D sketch shape polar IMB
Methane
______
Methanol
______
Hexane
______
Trichloromethane
3)Look up: A)-the melting point of all four substancesand B)-uses for each one on the internet and/or in a reference book.Group plan – divide these up and share information.
------MP in C------Uses------
Methane
______
Methanol
______
Hexane
______
Trichloromethane
______
4)Do these lab tests for methanolat one station and then hexane at the other station:
A)Flammability - add a few drops to the labeled Petri dish and attempt to light it with a match. If it is flammable, describe the flame. Group Plan – take turns with one person doing the test while others record information.
Be sure the container is closed & well away when lighting a match.
------flammable?------flame description------
Methanol-
Hexane-
B)Solubility in water: Water Station
- Fill the test tube labeled methanol & H2O about ½ way with water.
- Then add ~ 20 drops of the methanol.
- Put your finger over it, shake, wait for one minuteto see if it dissolvesor separates and record the results below.
- Repeat procedure with hexane in the test tube labeled hexane & H2O.
Methanol
Hexane
C)Solubility in cooking oil: Cooking Oil Station DO NOT RINSE THESE TUBES WITH H2O !!!
- Fill the test tube labeledmethanol/cooking oil about ½ way with corn oil.
- Then add ~ 20 drops of the methanol.
- Shake & wait for one minute to see if it dissolves or separates and record your results below.
- Repeat procedure with hexane in the test tube labeled hexane/cooking oil.
Methanol
Hexane
5)Watch the short film “Petroleum Refinery” answer these questions.
Navigate to the film by selecting – programs – departments- chemistry- CD 3 – Contents – Chapter 18 – Section 1 – Industrial Processes: Petroleum Refining.
Group plan - answer these questions as a group discussing the answers together!!
a)From what things did oil originally form and what caused it to form?
b)Name the process in which oil is separated into different organic compounds and describe how it works.
c)What are 4 organic materials that are made from oil & what is each one used for?
Analysis:Group plan - answer these questions as a group discussing the answers together!!
1)Methane is one of the main components of natural gas.
-Is it flammable?
-From what you have observed/know about the other three organic compounds in this lab, do you think Trichloromethane would be flammable?
-What about other organic compounds, are many of them likely to be flammable? If so what would be a common use for many organic compounds?
2) Trichloromethane, methanol, and methane are all small organic molecules that are about the same molecular size. Why is methane’s mp and bp so much lower that the other two compounds?
Since both hexane and methane experience dispersion IMB, why does hexane have a much higher mp and bp than methane?
3)Can you divide ALL organic compounds into two main groups by mp/bp? Explain.
4) Predict the solubility of methane, and also oftrichloromethane, in water, based on what you know and explain your reasoning.
Can you divide ALL organic compounds into two groups by solubility? Explain
5)Using only information from the research you have done, give the best definition you can for organic compounds, including information about: a) elements involvedb) bonding.
6) What are some: a) molecular characteristics, b) uses, and/or c) physical or chemical properties you have found that most organic compounds seem to share?
7)THE TWO MAIN CAETGORIES OF ORGANIC COMPOUNDS!
a) Divide the four organic compounds in this lab into two groups which could represent ALL organic compounds, giving each group a label.
b) Tell what properties each group has in common that make it different from the other group.