oxidation of food Flashcards
(16 cards)
What is oxidation in carbon compounds?
An increase in the oxygen to hydrogen ratio
Oxidation refers to the addition of oxygen or the loss of hydrogen.
What is reduction in carbon compounds?
A decrease in the oxygen to hydrogen ratio
Reduction involves the loss of oxygen or the gain of hydrogen.
What can hot copper(II) oxide or acidified dichromate(VI) solutions oxidise?
Primary alcohols to aldehydes and then to carboxylic acids; secondary alcohols to ketones
These are common oxidizing agents in organic chemistry.
What happens to copper(II) oxide during oxidation reactions?
Black copper(II) oxide forms a brown solid
This color change indicates a chemical reaction has taken place.
What color change occurs with dichromate solution during oxidation?
Orange dichromate solution turns green
This indicates the reduction of dichromate ions.
Can tertiary alcohols be oxidised using standard oxidising agents?
No
Tertiary alcohols do not undergo oxidation with these agents.
What functional group do aldehydes and ketones contain?
Carbonyl functional group O=C
The carbonyl group is key to the reactivity of these compounds.
What can be used to differentiate between an aldehyde and a ketone?
Oxidising agents
Specific tests yield different results for aldehydes and ketones.
What happens when blue Fehling’s solution is mixed with an aldehyde?
Forms a brick red precipitate
This is a classic test for aldehydes.
What occurs with Tollens’ reagent when an aldehyde is present?
Forms a silver mirror
This is another method to test for aldehydes.
What happens to acidified dichromate solution when it reacts with an aldehyde?
Turns green
This indicates the aldehyde is being oxidised.
What type of compounds are commonly found in flavours and aromas?
Aldehydes
Many natural and synthetic flavouring agents are based on aldehydes.
What causes the oxidation of food?
Oxygen from the air
This process can lead to rancidity in edible oils.
What are antioxidants?
Molecules that prevent unwanted oxidation reactions occurring
They are crucial in preserving food and protecting against oxidative damage.
How do antioxidants function in redox reactions?
They are substances that are easily oxidised and oxidise in place of the compounds they protect
This makes them effective in preventing oxidation.
In a redox equation, how can antioxidants be identified?
As the substance being oxidised
This highlights their role in the reaction dynamics.
