- Gentle warming
- Catalyst: a few drops of concentrated sulfuric acid
Month: November 2023
List the conditions for fermentation of glucose solution.
- Temp 37 deg C
- Absence of oxygen
- Biological enzyme: yeast
List the conditions for hydration of alkenes.
- Temp 300 deg C
- Pressure 60 atm
- Catalyst: Phosphoric(V) acid, H3PO4
List the conditions for hydrogenation of alkenes.
- Temp 200 deg C
- Catalyst: nickel
List the conditions for substitution reaction of alkanes.
Presence of UV light.
List the conditions for catalytic cracking of long chain alkanes.
- Temp 600 deg C
- Catalyst: aluminium oxide or silicon (IV) oxide
Write down the general formula for: alkanes, alkenes, alcohols, carboxylic acids.
Alkane: CnH2n+2
Alkene: CnH2n
Alcohol: CnH2n+1OH
Carboxylic acid: CnH2n+1COOH
List the percentage composition of air.
- Nitrogen (78%)
- Oxygen (21%)
- Carbon dioxide (0.03%)
- Noble gases (less than 1%, mainly argon)
- Water vapour (variable)
Explain, using structure and bonding, why silicon dioxide has high melting and boiling point.
Silicon dioxide has a giant molecular structure, consisting of a large number of silicon and oxygen atoms covalently bonded to form a big tetrahedral structure. A lot of energy is needed to break the strong covalent bonds, resulting in the high melting point and boiling point of silicon dioxide.
Describe the test for nitrate ions.
Add aqueous sodium hydroxide and aluminium foil into a sample of the solution, and warm gently. If a pungent colorless gas is produced, which turns damp red litmus blue, it shows the presence of nitrate ions.