Term
| __________ are hydrocarbons with carbon-carbon double bonds. |
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Definition
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Term
| Alkenes are sometimes called __________, a term derived from olefiant gas, meaning "oil-forming gas." |
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Definition
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Term
| __________ is the largest-volume industrial organic compound, used to make polyethylene and a variety of other industrial and consumer chemiclas. |
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Definition
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Term
| The bond energy of a carbon-carbon double bond is about __________ compared with the single-bond energy of about __________. From this information, we can determine that the value of a pi bond is about __________; this value shows that pi bonds should be more reactive than sigma bonds. |
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Definition
1) 611 kJ/mol
2) 347 kJ/mol
3) 264 kJ/mol |
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Term
| Since a carbon-carbon double bond is relatively reactive, it is considered to be a __________ __________ and alkenes are characterized by the reactions of their __________ __________. |
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Definition
1) Functional group
2) Double bonds |
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Term
| The __________ __________ __________ tells us that two pairs of electrons can go into the region of space between the carbon nuclei only if each pair has its own molecular orbital. |
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Definition
| 1) Pauli exclusion principle |
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Term
In ethylene, each carbon atom is bonded to three other atoms (one __________ and two __________), and there are no nonbonding electrons.
Three hybrid orbitals are needed, implying __________ hybridization with bond angles of about __________ to give optimum separation of the three atoms bonded to carbon.
The C-H bond length in ethylene is slightly shorter than the C-H bond in ethane because the sp2 orbital in ethylene has more __________ character (__________-__________ s) than an sp3 orbital (__________-__________ s). The __________ orbital is closer to the nucleus than the __________ orbital, contributing to shorter bonds. |
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Definition
1) Carbon
2) Hydrogens
3) sp2
4) 120
5) s
6) One-third
7) One-fourth
8) s
9) p |
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Term
| The C=C bond in ethylene (1.33 A) is much shorter than the C-C bond (1.54 A) in ethane, partly because the sigma bond of ethylene is formed from __________ orbitals (with more __________ character) and partly because there are __________ bonds drawing the atoms together. The second carbon-carbon bond is a __________ bond. |
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Definition
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Term
In ethylene, for pi overlap to occur, the __________ orbitals must be __________, which requires that the two carbon atoms be oriented with all their C-H bonds in a single plane.
Half of the pi-bonding orbital is __________ the C-C sigma bond, and the other half is __________ the bond. The pi-bonding electrons give rise to regions of high __________ __________. |
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Definition
1) p
2) Parallel
3) Above
4) Below
5) Electron density |
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Term
In ethylene (and other molecules that possess a double bond), the molecule cannot be twisted with respect to each other without disrupting the __________ bond.
Unlike single bonds, a carbon-carbon __________ __________ does not permit rotation.
Six atoms, including the double-bonded __________ atoms and the four other atoms attached must remain in the same plane; this is the origin of __________-__________ isomerism:
If two groups are on the same side of a double bond (__________) they cannot rotate to opposite sides (__________) without breaking the pi bond. |
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Definition
1) Pi
2) Double-bond
3) Carbon
4) Cis-trans
5) Cis
6) Trans |
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Term
| Alkenes are said to be __________ because they are capable of adding hydrogen in the presence of a catalyst. |
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Definition
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Term
| The product of an alkane is called __________ because it cannot react with any more hydrogen. |
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Definition
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Term
| The presence of a pi bond of an alkene (or an alkyne) or the ring of a cyclic compound decreases the number of __________ __________ in a molecular formula; these are known as __________ __________ __________. |
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Definition
1) Hydrogen atoms
2) Elements of unsaturation |
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Term
| Each element of unsaturation corresponds to __________ fewer __________ atoms than in the "saturated" formula. |
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Definition
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Term
To determine the number of elements of unsaturation, calculate the maximum number of hydrogen atoms from the saturated formula __________, and see how many are missing.
The number of elements of unsaturation is simply __________ the number of missing __________. |
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Definition
1) CnH(2n+2)
2) Half
3) Hydrogens |
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Term
| __________ are any atoms other than carbon and hydrogen. |
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Definition
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Term
Elements of Unsaturation with Heteroatoms
Halogens: Halogens simply substitute for hydrogen atoms in the molecular formula. In calculating the number of elements of unsaturation, simply count halogens as __________ atoms.
Oxygen: An oxygen atom can be added to the chain (or added to a C-H bond to make a C-OH group) without changing the number of __________ or __________ atoms. In calculating the number of elements of unsaturation, __________ the oxygen atoms.
Nitrogen: A nitrogen atom can take the place of a __________ atom in the chain, but nitrogen is __________, having only __________ additional hydrogen atom compared with __________ hydrogens for each additional carbon atom. In computing the elements of unsaturation, count nitrogen as __________ a __________ atom. |
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Definition
1) Hydrogen
2) Carbon
3) Hydrogen
4) Ignore
5) Carbon
6) Trivalent
7) One
8) Two
9) Half
10) Carbon |
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Term
| When calculating the elements of unsaturation, halogens simply substitute for hydrogen atoms in the molecular formula. In calculating the number of elements of unsaturation, simply count halogens as __________ atoms. |
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Definition
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Term
| In calculating elements of unsaturation, an oxygen atom can be added to the chain (or added to a C-H bond to make a C-OH group) without changing the number of __________ or __________ atoms. In calculating the number of elements of unsaturation, __________ the oxygen atoms. |
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Definition
1) Carbon
2) Hydrogen
3) Ignore |
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Term
| In counting the elements of unsaturation, a nitrogen atom can take the place of a __________ atom in the chain, but nitrogen is __________, having only __________ additional hydrogen atom compared with __________ hydrogens for each additional carbon atom. In computing the elements of unsaturation, count nitrogen as __________ a __________ atom. |
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Definition
1) Carbon
2) Trivalent
3) One
4) Two
5) Half
6) Carbon |
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Term
When a carbon chain has a double bond present and contains more than __________ carbon atoms, a number is used to give the location of the double bond.
The chain is numbered starting from the end __________ to the double bond, and the double bond is given the __________ number of its two double-bonded carbon atoms. |
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Definition
1) Three
2) Closest
3) Lowest |
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Term
| __________ are assumed to have their double bond in the number 1 position. |
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Definition
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Term
| In 1993, the IUPAC recommended a logical change in the positions of the numbers used in names. Instead of placing the numbers __________ the root name (1-butene), they recommended placing them immediately before the part of the name they locate (but-1-ene). The new placement is helpful for clarifying the names of compounds containing multiple __________ __________. |
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Definition
1) Before
2) Functional groups |
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Term
| A compound with two double bonds is a __________. |
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Definition
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Term
| A compound with three double bonds is a __________. |
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Definition
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Term
| A compound with four double bonds is a __________. |
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Definition
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Term
| When naming alkenes, each __________ __________ attached to the main chain is listed with a number to give its location. The __________ __________ is still given preference in numbering, however. |
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Definition
1) Alkyl group
2) Double bond |
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Term
| Alkenes named as substituents are called __________ __________. They can be named __________ (ethenyl, propenyl, etc.) or by __________ __________. |
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Definition
1) Alkenyl groups
2) Systematically
3) Common names |
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Term
| What are the four common akenyl substituents? |
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Definition
1) Vinyl
2) Allyl
3) Methylene
4) Phenyl (which is aromatic) |
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Term
| =CH2 is a __________ group (type of alkenyl group). |
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Definition
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Term
| -CH=CH2 is a __________ group (type of alkenyl group). |
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Definition
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Term
| -CH2-CH=Ch2 is a __________ group (type of alkenyl group). |
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Definition
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Term
| An aromatic alkenyl group is a __________ group. |
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Definition
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Term
| The process of hydrogenation is mildly __________, evolving about __________ to __________ of heat per mole of hydrogen consumed. |
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Definition
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Term
| A lower heat of hydrogenation corresponds to __________ energy and __________ stability of the alkene. |
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Definition
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Term
| The heat of hydrogenation is a measure of the energy content of the __________ bond. |
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Definition
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Term
| The heats of hydrogenation can be used to compare the stabilities of different alkenes as long as they __________ to give alkanes of similar __________. |
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Definition
1) Hydrogenate
2) Energies |
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Term
| The most stable double bonds are those with the most __________ groups attached. |
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Definition
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Term
| *Zaitsev's Rule essentially states that the more __________ double bonds are usually the __________ stable.* |
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Definition
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Term
| __________ groups attached to double-bonded carbons stabilize the alkene. |
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Definition
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