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Colour Practice Questions. May 2009(1) F2:. May 2011(1) F2:. State one difference between a dye and a pigment (1) Explain in terms of their effect on light, why these compounds are colored (1) State a common food, apart from carrots, in which the following classes of pigment are found: (2)

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colour practice questions
Colour Practice Questions

May 2009(1) F2:

May 2011(1) F2:

State one difference between a dye and a pigment (1)

Explain in terms of their effect on light, why these compounds are colored (1)

State a common food, apart from carrots, in which the following classes of pigment are found: (2)

Anthocyanin

A carotene

Identify ONE other colored compound found in uncooked foods (1)

Countries have different laws about the use of synthetic colorants in food. Explain why this can be dangerous for the consumer (1)

Artificial food colorants have recently been linked to increased hyperactivity in children. Many foods are colorful because of the natural pigments they contain

  • Explain why naturally-occurring pigments are colored (1)
  • State the class of pigments that give cranberries and strawberries their color (1)
  • Describe the effects of metal ions on the color of this pigment (1)
  • State the class class pigments that give carrots and tomatoes their color (1)
  • Outline why this class of pigment is susceptible to oxidation, and the effect of oxidation on this pigment (2)
colour practice questions1
Colour Practice Questions

May 2009(1) F2:

Key

They reflect/absorb different wavelengths of light

Anthocyanins

Metals form complexes which discolor anthocyanins

Carotenoids

They have double bonds which react easily; Oxidation causes color loss

Artificial food colorants have recently been linked to increased hyperactivity in children. Many foods are colorful because of the natural pigments they contain

  • Explain why naturally-occurring pigments are colored (1)
  • State the class of pigments that give cranberries and strawberries their color (1)
  • Describe the effects of metal ions on the color of this pigment (1)
  • State the class class pigments that give carrots and tomatoes their color (1)
  • Outline why this class of pigment is susceptible to oxidation, and the effect of oxidation on this pigment (2)
colour practice questions2
Colour Practice Questions

Key:

May 2011(1) F1:

State one difference between a dye and a pigment (1)

Explain in terms of their effect on light, why these compounds are colored (1)

State a common food, apart from carrots, in which the following classes of pigment are found: (2)

Anthocyanin

A carotene

Identify ONE other colored compound found in uncooked foods (1)

Countries have different laws about the use of synthetic colorants in food. Explain why this can be dangerous for the consumer (1)

  • a dye is a synthetic colouring substance and pigments occur naturally
  • the dye/pigment absorbs some colours/wavelengths/frequencies of light (whilst reflecting others)
  • (a) beetroot / red cabbage / blackcurrants / cherries / red grapes / named berries; (Accept any other correct answer, but must have specific names e.g. strawberries instead of berries.) (b) tomato / pumpkin / capsicum / bananas / squash / mango;
  • chlorophyll / hemoglobin / heme / myoglobin
  • labelling/safety regulations vary (considerably) between countries / a food produced in a country may be considered toxic in another / a toxic compound may not be banned in all countries / OWTTE