S3 Revision

1
S3 Revision Carbohydrates (Nat 4 information)

• Carbohydrates
• Carbohydrates are made from the elements
  carbon, hydrogen and oxygen.
• All carbohydrates produce carbon dioxide and
  water when they are burned in oxygen.
• Glucose and starch are both common
  carbohydrates.
• Starch is found in food stuff such as cereals,
  bread, rice, pasta and potatoes.
• We use Benedicts reagent to test for glucose.
  If glucose is present the Benedicts changes
  colour from blue to orange.
• We use Iodine solution to test for starch. If
  starch is present the iodine changes colour from
  dark red/brown to blue/black.
• Glucose can be turned into ethanol via the
  process of fermentation.
• As fermentation only gets the percentage of
  ethanol to a certain level (3-7), distillation
  is needed to make spirits (40)