What is Electronegativity?
- The ability of an atom to attract electrons
- The more electronegative an atom, the stronger it will hold onto electrons in a chemical bond
What is a polar covalent bond?
A bond were one of the atoms in it is more electronegative than the other so the bond has a slight charge
What is the basic principle of the solubility rules?
- “Like dissolves like”
- Polar dissolves polar
- Non-polar dissolves non-polar
Describe the dehydration of ethanol
- The chemical process whereby a water molecule is removed from ethanol, forming ethylene
- C2H5OH (l) –H2SO4–> C2H4 (g) + H20 (l)
- Conc sulfuric acid catalyst
Describe the addition of water to ethylene
- Hydration of ethylene is the process whereby a water molecule is added to ethylene, forming ethanol
- C2H4 (g) + H20 (l) –H3PO4–> C2H5OH (l)
- Conc phosphoric acid catalyst
Account for the many uses of ethanol as a universal solvent
- Ethanol is able to dissolve both polar and non-polar substances due to it’s molecular structure
- The OH- group is POLAR
- The CH3CH2+ group is NON-POLAR
Advantages of ethanol
- Renewable resource
- “Greenhouse neutral”: the CO2 absorbed by the crop can match the CO2 produced by combustion
Disadvantages of ethanol
- Engines must be modified to run on fuel containing more than 20% ethanol
- Engines wear down faster
Describe the conditions under which fermentation of sugars is promoted. Include equations
- Fermentation is the process in which glucose is turned into ethanol and carbon dioxide by the action of enzymes
- C6H12O6 (aq) –yeast–> 2C2H5OH (aq) + 2CO2 (g)
COND: - Presence of yeast cultures
- Exclusion of air
- 37’C temperature
Summarise the chemistry of the fermentation process
- Yeast is added to mashed grain an water
- The yeast breaks down the large carbohydrates into simple sugars
- These sugars are then fermented
- The yeast use their enzymes to break down the sugars, forming ethanol and CO2 as products
Suffixes of naming more than one hydroxyl group
1 -ol
2 -diol
3 -triol
4 -tetraol
