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30 Cards in this Set
- Front
- Back
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Define Stereoisomerism |
Compounds either thr same molecular formula and bond arrangement but digger in the arrangement kr their atoms in space |
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What are E/Z isomers |
A type of stereoismer Occurs in alkenes Pi bonds restrict rotation about the double carbon to carbon bond |
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What do we need for E/Z isomers to form? |
Different groups attached to each carbon of the double bond Double carbon to carbon bond |
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What are the difference between E and Z isomers? |
Z isomers have the priority groups on the same level E isomers have the priority groups on different levels |
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How do you assign priority? |
Look at the Atomic number of each element If they are the same you move to the next element until there is a difference so you can compare them |
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Markownikoff's Rule |
The hydrogen will be added to the carbon with the most hydrogen atoms already bonded it The main product produced will follow this rule and the second product will have the H added to the other carbon The hydrogen will be added to the carbon with the most hydrogen atoms already bonded it The main product produced will follow this rule and the second product will have the H added to the other carbon The hydrogen will be added to the carbon with the most hydrogen atoms already bonded it The main product produced will follow this rule and the second product will have the H added to the other carbon |
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What is Carbocation Stability |
The positive charge on a carbocation is stabilised by electron-pushing alkyl groups (attached to the carbon with the positive charge) Tertiary Carbocation > secondary > primary |
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What is the different types of carbocation |
What we produce the most of: Tertiary > secondary > primary
Tertiary: Positive carbon has 3 bonds to 3 alkyl groups
Secondary: Positive carbon has 2 bonds to 2 alkyl groups
Primary: Positive carbon has 1 bond to 1 alkyl group |
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What is an alkyl group? |
Alkyl group is formed by removing a hydrogen atom from the molecule of alkane Often represented as R-H and here R stands for alkyl group. |
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Why is the major product most produced? |
Produces the most stable carbon cation so is produced the most |
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What does carbocation Stability explain? |
Markownikoffs rule |
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How do we name a compound using Z and E isomers? |
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What is pi bond |
A bond formed by the sideways overlap of 2 p orbitals, with the electron density above and below the plane of the bonding atoms |
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What conditions does a molecule have to satisfy to have E/Z isomerism |
A C=C bond Different groups attached to each carbon atom of the double bond |
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What type of bond does a C=C have |
1 sigma bond 1 Pi bond |
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What type of bond does a single bond have? |
1 Sigma bond |
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Why is a Pi bond weaker than a sigma bond? |
Broken more readily The pi electron density is concentrated above and below the the plane of the sigma bond in the C=C It being on the outside makes it more exposed |
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What happens if the atomic number of the atom attached to the carbon in the C=C bond is the same? |
Work your way outwards until you come to a 'point of difference'. The group with the atom with a higher atomic number at that point is the one with the higher priority |
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What type of addition reactions do alkenes undergo |
Each of these reactions involve the addition of a small molecule across the double bond causing the pi bond to break Hydrogen in the presence of a nickel catalyst (hydrogenation) Halogens (halogenation) Hydrogen halides Steam in the pressence of an acid catalyst (hydration) |
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Describe the hydrogenation of alkenes |
Reacted with hydrogen and passed over a nickel catalyst at 423K
Forms an alkane |
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Describe the halogenation of alkenes |
The addition of an halogen across the double bond of an alkene - breaks double bond The addition of an halogen across the double bond of an alkene - breaks double bond |
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How do we test for a double bond |
Use bromine water Positive Result: Colour change from orange to colourless Negative: No colour change, stays orange |
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Describe the reaction an of alkene with hydrogen halides |
Reaction takes place at room temp to form haloalkenes
If the alkene is a gas, the reaction takes place when the 2 gases are mixed
If the alkene is a liquid, then the hydrogen halide is bubbled through it
Alkenes also react with concentrated HCL or HBr |
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Describe the hydration of alkenes |
Forms alcohols
Alkenes react with steam in the presence of phosphoric acid catalyst, H3PO4 |
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What is electrophile addition? |
Addition reactions that form saturated compounds |
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What is an electrophile? |
An atom or group of atoms that is attracted to an electron-rich centre and accepts an electron pair. Usually a positive ion or a molecule containing an atom with a partial positive charge |
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Describe the electrophilic addition reaction of But-2-ene with HBr |
Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product Bromine is more electronegative than H, so HBr is polar Electron pair in the Pi bond is attracted to the partially positive H atom, Double bond breaks Bond forms between the H atom of the HBr molecule and a carbon atom that was part of the double bond HBr bond breaks by heterolytic fission, with the electron pair going to the bromine atom A bromide ion and a carbocation are formed. A Carbocation contains a positively charged carbon atom In the final step the Br ion reacts with the carbocation to form the addition product |
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Describe the mechanism reactoin between propene and Br-Br |
The electron pair in the pi bond is attracted to the Br+ end of the molecules, double bond breaks A bond is now formed between one of the carbon atoms from the double bond and a bromine atom The Br-Br bond breaks by heterolytic fission, electron pair goes to Br- end of the molecule Bromide ion and a carbocation is formed Br- ion reacts with the carbocation to form the addition product of the reaction The electron pair in the pi bond is attracted to the Br+ end of the molecules, double bond breaks A bond is now formed between one of the carbon atoms from the double bond and a bromine atom The Br-Br bond breaks by heterolytic fission, electron pair goes to Br- end of the molecule Bromide ion and a carbocation is formed Br- ion reacts with the carbocation to form the addition product of the reaction The electron pair in the pi bond is attracted to the Br+ end of the molecules, double bond breaks A bond is now formed between one of the carbon atoms from the double bond and a bromine atom The Br-Br bond breaks by heterolytic fission, electron pair goes to Br- end of the molecule Bromide ion and a carbocation is formed Br- ion reacts with the carbocation to form the addition product of the reaction The electron pair in the pi bond is attracted to the Br+ end of the molecules, double bond breaks A bond is now formed between one of the carbon atoms from the double bond and a bromine atom The Br-Br bond breaks by heterolytic fission, electron pair goes to Br- end of the molecule Bromide ion and a carbocation is formed Br- ion reacts with the carbocation to form the addition product of the reaction The electron pair in the pi bond is attracted to the Br+ end of the molecules, double bond breaks A bond is now formed between one of the carbon atoms from the double bond and a bromine atom The Br-Br bond breaks by heterolytic fission, electron pair goes to Br- end of the molecule Bromide ion and a carbocation is formed Br- ion reacts with the carbocation to form the addition product of the reaction The electron pair in the pi bond is attracted to the Br+ end of the molecules, double bond breaks A bond is now formed between one of the carbon atoms from the double bond and a bromine atom The Br-Br bond breaks by heterolytic fission, electron pair goes to Br- end of the molecule Bromide ion and a carbocation is formed Br- ion reacts with the carbocation to form the addition product of the reaction The electron pair in the pi bond is attracted to the Br+ end of the molecules, double bond breaks A bond is now formed between one of the carbon atoms from the double bond and a bromine atom The Br-Br bond breaks by heterolytic fission, electron pair goes to Br- end of the molecule Bromide ion and a carbocation is formed Br- ion reacts with the carbocation to form the addition product of the reaction The electron pair in the pi bond is attracted to the Br+ end of the molecules, double bond breaks A bond is now formed between one of the carbon atoms from the double bond and a bromine atom The Br-Br bond breaks by heterolytic fission, electron pair goes to Br- end of the molecule Bromide ion and a carbocation is formed Br- ion reacts with the carbocation to form the addition product of the reaction The electron pair in the pi bond is attracted to the Br+ end of the molecules, double bond breaks A bond is now formed between one of the carbon atoms from the double bond and a bromine atom The Br-Br bond breaks by heterolytic fission, electron pair goes to Br- end of the molecule Bromide ion and a carbocation is formed Br- ion reacts with the carbocation to form the addition product of the reaction |
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What is a carbocation? |
An ion with a positively charged carbon atom |
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What are cis, trans isomers |
Cis isomers (Z) has pairs of the same atoms on each carbon on the same side Trans isomers (E) has pairs of the same atoms on each carbon on opposite sides Cis isomers (Z) has pairs of the same atoms on each carbon on the same side Trans isomers (E) has pairs of the same atoms on each carbon on opposite sides Cis isomers (Z) has pairs of the same atoms on each carbon on the same side Trans isomers (E) has pairs of the same atoms on each carbon on opposite sides Cis isomers (Z) has pairs of the same atoms on each carbon on the same side Trans isomers (E) has pairs of the same atoms on each carbon on opposite sides Cis isomers (Z) has pairs of the same atoms on each carbon on the same side Trans isomers (E) has pairs of the same atoms on each carbon on opposite sides |
