Consider a simple chemical reaction where the forward reaction occurs in a singl
ID: 1063056 • Letter: C
Question
Consider a simple chemical reaction where the forward reaction occurs in a single step and the reverse reaction occurs in a single step: The following chemical reaction, where cis-2 butene is converted into trans-2-buterie, is an example. In this example, one end of a cis-2-butene molecule routes 180 degree to form a trans-2-butane molecule. Rotation around a double bond rarely happens at room temperature because the collisions are not sufficiently energetic to weaken the double bond. At higher temperatures, around 400 degree C for cis-2-butene, collisions are sufficiently energetic and an appreciable reaction rate is detected. Critical Thinking Questions: In most molecular model kits, black = C and white = H. Short bonds are used for single bonds and two of the longer, flexible bonds are used for double bonds. a. Have one team member make a model of cis-2-butene with a modeling kit. b. Have a second team member make a model of trans-2-butene. Examine the models as a team. What must be done to convert cis-2-butene to trans-2-butene? What must be done to convert trans-2-butene to cis-2-butene? Can the molecules be interconverted without disconnecting ("breaking") the bonds? A large number of cis-2-butene molecules is placed in a container. a. As a team, predict what will happen if these molecules are allowed to stand at room temperature for a long time. Write your team answer In a complete sentence. b. As a team, predict what will happen if these molecules are allowed to stand at 400 degree C for a long time. Write your team answer in a complete sentence. Adapted from ChemActivity 37, Moog, R.S. and Farrell, J.J. Chemistry: A Guided Inquiry. 5^th ed. Wiley, 2011, PP. 211-216.Explanation / Answer
2. Transformation of cis-2-butene to tras-2-butene is acheived by breaking the C=C bond in between the to carbons.
3. Again the conversion of trans-2-butene to cis-2-butene can be achieved by breaking the C=C bond.
4. The conversion is not possible without breaking the carbon carbon bonds in between.
5. If cis-2-butene is placed in a container and allowed to stand at,
a. Room temperature : nothing would happen
b. at 400 oC : conversion of cis-2-butene to trans-2-butene would occur.