Lecture 8 Flashcards
(24 cards)
What are Functional Groups ?
Specific groups of atoms within molecules
Responsible for the characteristic chemical and physical properties of those molecules
The site of reactivity in an organic molecule is the functional group
Linked together within the molecule by covalent bonds
What is a hydrocarbon? with examples
Hydrocarbons are chemical compounds consisting of carbon and hydrogen Form the backbone of organic compounds gas (methane and propane) liquids (hexane and benzene) wax (paraffin wax) polymers (polyethylene and polystyrene)
What are the four types of hydrocarbons?
- Saturated hydrocarbons, consisting of only single bonds between carbon atoms
- Unsaturated hydrocarbons, with double or triple bonds
- Cycloalkanes, with consist of hydrogen bonded to carbon rings
- Aromatic hydrocarbons, which contain a chemical structure known as an aromatic ring, e.g. benzene
What are Alkanes?
Saturated hydrocarbon Only carbon and hydrogen All single bonds Their names end with –ane Ethane
What are Alkenes?
Unsaturated hydrocarbon Only carbon and hydrogen A carbon to carbon double bond Their names end with –ene Ethene
What are Alkynes?
A carbon to carbon triple bond
Their names end with –yne
Unsaturated hydrocarbon
What are Hydroxyl Groups?
-OH group in a covalent bond is known as hydroxly group
Does not ionize – covalent bond
Covalent bonds are strong, they do not break when in water
Ionic compounds dissolve easily in water
OH group is polar covalent bond
Alcohols are soluble in water
Alcohols can have one or more –OH groups
General formula: R—OH (hydroxyl functional group)
Methanol, Antifreeze
What is a carbonyl group?
Contain the functional group C=0
Composed of a carbon atom double-bonded to an oxygen atom:
C=O
At least one H atom must be bonded to the C in the carbonyl group
General name: Root name of the hydrocarbon chain + “al”
What are Aldehydes ?
Under mild oxidation conditions, alcohols can convert to aldehydes and ketones
Aldehydes – The carbonyl group (C=0) must be at the end of a carbon chain
Polar carbonyl group makes aldehydes water-soluble
Aldehydes are powerful disinfectants (formaldehyde)
What are Ketones?
The carbonyl group (C=0) must be in the middle of a carbon chain – two “R” groups
General name: Root name of the hydrocarbon chain + “one”
Polar carbonyl group makes ketones water-soluble
Ketones are responsible for many flavors and odors in foods and perfumes
What are organic acids?
The group COOH is called the carboxyl group
Have C=O and OH groups on the same carbon atom
Ethanoic acid
Root name of hydrocarbon chain + oic acid
Called carboxylic acids (yield H+)
Organic acids with long hydrocarbon chains called fatty acids and are found in fats
What are esters?
They are made from two hydrocarbon chains joined by a ‘COO’ group
One oxygen is part of a C=O bond, the other is between two carbons
They are named as Alkylalkanoate, Methylethanoate
R chain name + “yI” and R name + ‘oate’
Esters are broken down into organic acids and alcohols
Fats and oils are esters
What are amines?
Organic compounds containing an amino / functional group (NH2) are called amines
Amines are derivatives of Ammonia (NH3)
General formula: R — NH2
General name: Root name of the hydrocarbon chain + “amine”
They neutralize acids by absorbing H+
They are weak bases
Aniline - carcinogenic
What are amino acids?
Compounds with both an amine group and a carboxyl group attached to the same carbon of the hydrocarbon chain
They are the basic building blocks of protein
When the body metabolizes an amino acid, ammonia is formed
In PKU (Phenylketonuria), phenylalanine is not metabolized
Accumulates in the bloodstream and causes brain damage
Test done as part of the Newborn Screening profile (for genetic defect metabolism) ie Phenylalanine
What are amides?
Have NH2 and C=O groups on the same carbon atom
Contain a carbonyl group followed by either NH2 or NHR
They are named as alkanamide
Root name of hydrocarbon chain: amide
Amide bonds / hold amino acids in long chains known as proteins
What are phosphates?
High energy compounds are formed by linking several phosphates together
AMP: low energy
ATP: high energy
What are Sulfhydryl Groups?
General formula: R — SH
Example: Cysteine
What is a Spectrophotometer?
Thespectrophotometeris an optical instrument for measuring the intensity of light relative to wavelength
It can measure the amount of light or electromagnetic radiation (of certain frequency) transmitted or absorbed by the solution
What is a Spectrophotometer used for?
Spectrophotometric techniques are used to measure the concentration of solutes in solution by measuring the amount of light that is absorbed by the solution in a cuvette placed in the spectrophotometer
What are the properties of light?
The colour of light is determined by its wavelength
White light is made of many colours or wavelengths
Coloured solutions are coloured because they absorb some colours or wavelengths from white light
What is electromagnetic radiation?
Electromagnetic radiation is a type of energy that is transmitted through space as a transverse wave at enormous velocity (wavelength)
The electromagnetic spectrum include gamma ray, X-ray, ultraviolet (UV), visible, infrared (IR), microwave and radio-wave radiation
Visible light ranges from 400-750nm
How does matter adsorb radiation
Polychromatic light (white light), is passed through a solution
The solution will absorb certain of the wavelengths, leaving the unabsorbed wavelengths to be transmitted
These residual transmitted wavelengths will be seen as a color
This color is complementary to the absorbed colors
What are cuvettes?
Usually round or square Made of material that does not absorb light in the wavelength range of interest Glass – visible region Quartz – ultraviolet A blank cuvette is used to calibrate the instrument Must be scratch free Clean with kimwipe or lens paper
What are the Conditions affecting the Spectrophotometer?
Temperature Humidity Vibration Electromagnetic interference Dust Radio frequency interference Fumes Radioactive contamination
