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The abundance of __ in nature is probably due to both their stability and the __ offered by their predictable conformations.
- cyclohexane rings
- selectivity
-
The combustion data show that cyclohexane has __.
It must have bond angles near the __ (no __) ad also have no __ ( no __).
- no ring strain
- tetrahedral angle (no angle strain)
- eclipsing of bonds (no torsional strain)
-
A planar, regular hexagon would have bond angles of 120 rather than 109.5, implying some __. A planar ring would also have __ because the bonds on adjacent CH2 groups would be __. Therefore, the cyclohexane ring cannot be __.
- angle strain
- torsional strain
- eclipsed
- planar
-
Cyclohexane achieves __ and __ by assuming the __. The most stable conformation is the __.
- tetrahedral bond angles
- staggered conformations
- puckered conformation
- chair conformation
-
In the chair conformation, the angles between the carbon-carbon bonds are all __.
109.5
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The __ of cyclohexane also has bond angles of 109.5 and avoids __. It resembles the __ except hte footrest is folded upward. It sufferes from __ because there is __ of bonds.
- boat conformation
- angle strain
- chair conformation
- torsional strain
- eclipsing
-
This eclipsing forces two of the hydrogens on the ends of the "boat" to interfere with each other. They are called __ because they point upward from the ends of the boat like two.
flagpole hydrogens
-
A cyclohexane molecule in the boat conformation actually exists as a slightly skewed __: The __ move away from each other and the __ of the bonds is reduced.
- twist boat conformation
- flagpole hydrogens
- eclipsing
-
Even though the __ is lower in energy than the __, it is still about 23 kJ/ mol higher in energy than the __.
- twist boat
- symmetrical boat
- chair conformation
-
At any instant, most of the molecules in a __ sample are in __. The energy barrier between the boat and chair is sufficiently __, that the conformations interconvert many times each second.
-
The __ from the chair to the boat takes place by the footrest of the chair flipping upward to form the boat.
interconvverson
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the highest-energy point in this process is the conformation where the footrest is __ with the sides of the molecule. This unstable arrangement is called the __.
- planar with the sides of the molecule
- half-chair conformation
-
There are two types of __ in cyclohexane's __.
- carbon-hydrogen
- chair conformation
-
Six of the bonds (one on each carbon atom) are directed __ and __, parallel to the __. These are called __.
- up and down
- axis of the ring
- axial bonds
-
The other six bonds point out from the ring, along the __ of the ring. These are called __.
-
Each carbon atom in cyclohexane is __.
bonded to two carbon atoms, one directed upward and one downward
-
The odd numberd carbon atoms have __. The even numbered carbon atoms have __.
- axial bonds up and equatorial bonds down
- equatorial bonds up and axial bonds down
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