3.4 Carbohydrates Flashcards
Define Carbohydrates
Carbohydrates are poly-hydroxyl aldehydes or poly-hydroxyl ketones.
What is the oxygen to hydrogen ratio in a carbohydrate?
oxygen : hydrogen
1 : 2
(Cx H(2y) Oy)
What is the suffix for carbohydrates?
-ose
What is the molecular formula for glucose?
C6 H12 O6
What is the molecular formula for fructose?
C6 H12 O6
What is the molecular formula for sucrose?
Disaccharide - C12H22O11
How di- , tri- and poly- saccharides formed?
They are formed through the condensation of monosaccharide units in a chain by covalent bonds
What is glucose?
The common respiratory fuel
What is glucose the monomer of?
Monomer for natural poly-saccharides such as amylose (starch) or cellulose
What is the relationship between the ring and chain form of glucose?
The ring and chain form will achieve an equilibrium.
What side will be favoured in the ring/chain equilibrium?.
The ring form will be favour 60% to 40%
How can the ring and chain form of glucose be identified?
The chain form has an exposed aldehyde and thus will be selectively oxidised using ammoniacal silver nitrate - any sugar that reacts with ammoniacal silver nitrate is termed a reducing sugar.
What does the cyclic form of glucose form?
Polymerises to form di- and poly- saccharides
Can di- and poly- saccharides be reducing sugars?
No - they do not have an exposed aldehyde - are made up of ring form of glucose
Name a common poly-saccharide
Starch - amylose
What carbohydrates are soluble in water?
Simple carbohydrates are soluble in water.
What are simple carbohydrates?
They contain one hydroxyl for every five carbons
Which carbohydrates are not soluble in water?
Poly-saccharides are not soluble in water as they are too large. However, they are hydrophilic.
Colour change of bromine
Brown/yellow to colourless
OR
Purple to colourless
Describe the reaction of bromine and an alkene
Will react quickly in the dark and change from brown/purple/yellow to colourless.
This is known as an addition reactions and only one product is formed as the bromine breaks the double bonds
Describe the reaction of bromine and an alkane
Slow substitution reaction with two products formed.
This reaction is non-directed and any hydrogen can be replaced
What is the prefix used when naming halogen hydrocarbons?
Bromine - bromo
iodine - iodo
chlorine - chloro
Draw straight chain glucose
Check desktop /chemistry folder
Draw ring form glucose
Check desktop / chemistry folder