Oxidation of food Flashcards
State what in an ion electron equation indicates that vitamin c is acting as an antioxidant
increase in O:H ratio
loss of electrons
State the characteristic which some aldehydes and ketones give food
they give off aromas which contribute to
the flavour of some foods
Explain why volatility of compounds is important in cooking
The smell of the molecules contributes
to the flavour of the food. The more
volatile the compounds then the more
likely they are to be given off during
cooking.
Explain why aldehydes and ketones are soluble in water
The carbonyl group is polar and can
form hydrogen bonds with the polar
water molecules
What can be used to oxidise primary and secondary alcohols
hot copper(II) oxide
acidified dichromate(IV) solutions
What does the black copper oxide form when it oxidises alcohols
brown solid
What does orange dichromate solution turn after oxidising alcohols
green
Describe terpenes
can be oxidised within plants to produce some of the compounds responsible for the distinctive aromas of spices
What is a major cause of food spoilage
oxidation
What does oxygen react with that causes things to become rancid
react with fatty acids in fats and oils
Give an example of a reducing agent
carbon monoxide
Give examples of strong oxidising agents
hydrogen peroxide a
acidified permanganate
acidified dichromate solution
What is hydrogen peroxide useful for
a bleaching agent to remove colour from materials
Describe how apparatus could be used to show that olive oil has a higher degree unsaturation than coconut oil
bromine solution is added to both oils until the bromine is no longer decolourised
more bromine would be required for the more unsaturated
Suggest why hexane is used as a solvent rather than water
hexane is a non polar solvent
Give reasons why coconut oil has a higher melting point than olive oil
coconut oil molecules can pack more closely together
the van der waals forces between the molecules in coconut oil is stronger
Suggest why ibuprofen is only slightly soluble in water
it has a large hydrocarbon section/ non polar chain
In a reaction why is it essential to ensure the acid used is in excess
to ensure all of the substance had reacted
What oxidising agents are used for alcohols
hot copper(II) oxide
acidified dichromate
What oxidising agents are used for aldehydes
Fehlings solution
Tollens reagent 1
Why cant tertiary alcohols be oxidised
there is no free hydrogen on the carbon containing the hydroxyl group
What conditions are dichromate and permanganate ions strong oxidising agents in
acidic solutions
What can oxidising agents be used for
kill fungi/bacteria
inactivate viruses
What is the molar volume
the volume occupied by one mole of any gas at a certain temperature or pressure
Describe a chemical test with the expected result for both compounds that could be used to distinguish between a primary and secondary alcohol
Acidified dichromate changes from
orange to green
with methanol AND no colour change
would be observed with propan-2 one.
