Chapter 14 Flashcards
(21 cards)
Uses of methanol
Feedstock, solvent, paints, adhesives
Uses of ethanol
Solvent, alcoholic drinks, fuel, hand sanitiser, perfumes
Alkanes vs. alcohols
Bond polarity
Alkanes: Non-polar bonds (C-H)
Alcohols: Polar molecules, permanent dipole bc of electroneg. O atom/O-H bond
Volalitily
How easily a substance turns into a gas (higher boiling point = less volatile)
Alkanes vs. alcohols
Volatility and boiling points
Alcohols more volatile/lower BP than alkanes bc alcohols have PD, London forces and hydrogen bonds but alkanes only have London forces
(Many alkanes are gases at room temp.)
Alkanes vs. alcohols
Solubility
Alcohols more soluble than corresponding alkanes
Solubility decreases as chain length increases
What are the two ways to make ethanol?
Fermentation and hydration of alkenes
Describe the process of fermentation to make ethanol
- Yeast undergoes anaerobic respiration
- Carbohydrates -> ethanol + CO2
- ## Carbohydrates usually = sugar, e.g. glucose
Describe the process of hydration of ethene
- Steam and acid catalyst (usually phosphoric)
- Conditions: 300°C and 60 atm
Advantages of hydration of ethene
No waste
Disadvantages of the hydration of ethene
- Reversible so not 100% yield
- Conditions expensive to maintain
Dehydration is where an _______ is turned into a _______
Alcohol
Alkene
What catalysts are used in dehydration?
concentrated H3PO4 (phosphoric) or H2SO4
Dehydration of alcohols is h______ u_______ r_______
Heated under reflux
Primary alcohol
OH group is attached to carbon that is bonded to 1 alkyl groups (has 2 pr 3 hydrogens)
Examples of primary alcohols
Methanol, propan-1-ol
Secondary alcohol
OH group is attached to carbon that is bonded to 2 alkyl groups (carbon has 1 hydrogen)
Tertiary alcohol
OH group is attached to a carbon that is bonded to 3 alkyl groups (no hydrogens)
Combustion of alcohols requires …
XS oxygen
Complete combustion of alcohols produces …
CO2 and H2O
Combustion of alcohols is a ______ reaction
Exothermic
