Organic Chemistry and Carbon Bonding Flashcards
What is the historical definition of organic chemistry?
The chemistry of living things
-compounds obtained from living organisms were thought to poppies vital force that differentiated them from inorganic chemicals
Who synthesised urea from ammonium cyanate?
Wohler
What was synthesised in 1958?
Synthesis of Perkin’s mauve
What is the modern definition of organic chemistry?
The chemistry of compounds of carbon
What forms can organic compounds come in?
- Colourless, coloured
- Gases, liquids or solds
- Waxes
- Plastics
- Odorous or odourless
Finish the sentence:
If we want to understand life processes on a molecular level we nee to understand the….
Structure of organic molecules
What do the properties of organic molecules depends on?
Structure of molecule
What is a deoxyribonucleic acid (DNA) relating to organic chemistry?
Carbon forms part of the sugar phosphate backbone and the attached bases
What is protein relating to organic chemistry?
Carbon forms part of the peptide backbone and attached side chains
What is fatty acids to organic chemistry?
Carbon, hydrogen and oxygen containing molecules (Saturated - no double bonds or unsaturated - double C=C bonds)
How are proteins and fatty acids made up by?
Biologically catalysed chemical reactions
Fill in the sentence:
Carbon has the ability to bind …. to other elements and for strong bonds with its …..
1) Strongly
2) Itself
What does carbon have a rare tendency to do?
Catenate
What is meant by catenate?
Form chains of carbon atoms
What does the carbon allow being able to catenate?
Allows a vast range of structure and therefor properties
What is carbons electron configuration?
1s2 2s2 2p2
What does carbon require to have a full valance?
4 extra electrons
What are the Lewis structures?
Dot and cross structures to display covalent bonding between molecules
What is wrong with the Lewis structure?
Does not attempt to explain the geometry of molecules, how bonds are formed or how electrons are shared between atoms
Define atomic orbital:
Region within an atom which can hold up to two electrons with opposite spins
What are the 4 meaningful types of orbitals?
s, p, d or f
Finish the sentence:
Each orbital has a…
specific shape
What are orbitals arranged into?
Groups of similar energies
What is principle quantum number (n)?
Related to the energy of an orbital
What is molecular orbital theory?
Two half-filled atomic orbitals combine to give a single or s-bond (sigma) consisting of two s-molecular orbitals
What does a double bond consist of?
s-bond and a p-bond
What does a molecular orbitals with double bonds form?
-Two p orbitals can overlap end-on, to form two s-molecular orbitals
OR
-Two p orbitals can overlap side-on, to form two p-molecular orbitals
What is the ground state?
The lowest state
If a carbon was to remain at a ground stat in a molecule it must:
- Share two electrons
- Only have 6 electrons in its valance orbital
1s atomic orbital + 2s atomic orbital =
Have correct symmetry to form sigma bond
1s atomic orbital + 2px orbital =
Have the correct symmetry to form a sigma bond
1s atomic orbital + 2py orbital =
Do no have the correct symmetry
What is the hybrid model?
Mathematically, energetically favoured in the resting molecular compound
What is orbital hybridisation?
2s orbital and 2p orbitals are mixed to give sp3 hybrid orbitals
What does it mean if orbital hybridisation happens?
Carbon can form 4 covalent bonds to fulfil the octet rule
What happens in methane relating to hybrid orbitals?
Sp3 orbitals mixes with hydrogen s orbital to form 4 sigma bonds to four hydrogen atoms
What is the bond angle in methane?
109.5 bond angle
Why does a tetrahedral arrangement occur?
Mutual repulsion will push the molecular orbitals as far apart as possible
Describe ethane in relation to hybrid orbitals:
- Three sp3 orbitals mix with the s orbitals of three hydrogen atoms to from three sigma bonds
- One sp3 orbital mixes with an sp3 orbital from second carbon atom forming c-c sigma bond
How do you achieve double carbon bond?
Having three sp2 hybrid orbitals and one unhybridized p orbital
What is an sp2 orbital hybridisation?
One s orbital and two p orbitals
Describe ethene in terms of orbital hybridisation:
Each carbon atom forms three sigma bonds:
- 2 to two hydrogen atoms
- 1 to second carbon atom (causing an overlap of sp2)
Each carbon atom forms a pie bond to the second carbon atom (overlap of unhybridized p orbitals)
Which bond is stronger sigma or pie bond?
Sigma
Describe sigma bond:
- End-on overlap (more effective)
- 346 Kjmol^-1
- Stronger
- Less reactive
Describe pie bond:
- Edgewise overlap (less effective)
- 252 KJmol^-1
- Weaker
- More reactive
How do you achieve a triple carbon bond?
2x sp hybrid orbitals
2x unhybridized orbitals
p orbital define the geometry around the carbon atom and the others try and position as far as possible
-one sigma bond
-2 pie bonds (overlap of unhybridised p-orbitals)
