Flashcards
CfE Higher Chemistry - Unit 2: Nature's Chemistry - Chemistry of Cooking and Oxidation of Food
Cards in this deck (22)
- 1Why are volatile molecules important for flavour?They are not freed until the cell walls are broken in cooking
- 2Name 2 oil-soluble funtional groupsAlkene C=C
Phenyl (C6H5) - 3Name 2 water soluble functional groupsCarbonyl C=O
l
H
Ester Link - 4Why do proteins change shape when heated?Heat breaks intermolecular bonds
- 5Functional Group present in Alcohols?Hydroxl (-OH)
- 6What is the difference between primary, secondary and tertiary alcohols?Primary - No more than one carbon is bonded to that bonded to the OH group
Secondary - No more than two (mid chain) "2/3-ol"
Tertiary - three "methyl........ 2/3-ol" - 7What is a cycloalkanol?Secondary alcohols in a ring structure
- 8Oxidation of Primary alcohol forms:an aldehyde and water
- 9What is an aldehyde?Functional group: CHO occuring at the end of the chain
Example: ethanAL - 10Oxidation of Aldehyde forms:Carboxyllic Acid
- 11Oxidation of a Secondary alcohol forms:Ketone
- 12What is oxidation?Loss of Hydrogen or gain of oxygen ina molecule
- 13What oxidising agent is used to oxidise primary and secondary alcohols and what colour change is shown?Acidifies potassium dichromae
orange -> green - 14What is a ketone?Funtional group: CO occurs within chain
Example: hexan-3-ONE - 15Benedict's Solution colour change:Blue -> Red
presence of aldehyde - 16Tollen's Reagent colour change:Silver Mirror forms in presence of aldehyde
- 17What are antioxidants?molecules which prevent oxidation from aking place and instead cause reductions by undergoing oxidation themselves.
- 18Give an example of antioxidantAscorbic acid
Vitamin C
Melatonin
Beta-carotene - 19Why are antioxidants added to food?to slow the rate of oxidationa dn extend the shelf lifeof the food.
- 20What are free radicals?atoms or molecuels which contain unpaired electrons and therefore pick up electorons from other atms, converting them into secondary free radicals
- 21What are the negative effects of free readicals?They can break strands of DNA
Too many can attack the cell membranes causing tisue damage - 22What is done to stop the effects of free radicals?Antioxidants provide electrons to free radicals
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- CfE Higher Chemistry - Unit 2: Nature's Chemistry - Chemistry of Cooking and Oxidation of Food
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