Give one reason why vegetable oils are important foods and fuels (1)

Size: px

Start display at page:

Download "Give one reason why vegetable oils are important foods and fuels (1)"

Dominick Higgins
5 years ago
Views:

1 C.6 PLANT OILS South Axholme School Q.Useful materials, including foods and fuels, are produced from plants. (a) Some plants have seeds that contain vegetable oils. (i) Give one reason why vegetable oils are important foods and fuels. () State the two main stages used to extract a sample of vegetable oil from seeds. (2) One property of a vegetable oil gives the oil an advantage over water for cooking foods. Explain how (2) (c) Vegetable oils and water do not mix. An emulsion is made by shaking a vegetable oil and water with an emulsifier, as shown below. Explain how the emulsifier molecules are able to produce an emulsion that is a stable mixture containing the vegetable oil and water. Use the diagram of the emulsifier molecule to help you to answer this question. Page

2 (4) (Total 9 marks) Q2. Olive oil is used to make salad dressings and margarine. (a) Vinegar is often used to make salad dressings. Vinegar contains 95% water and 5% ethanoic acid. To make a simple salad dressing add olive oil to vinegar and shake. After a few minutes the mixture separates. To make a French salad dressing add mustard to the olive oil and vinegar and shake. After several minutes the mixture does not separate. (i) Why does the mixture in the simple salad dressing separate? () Mustard in the French salad dressing has molecules with hydrophilic properties and hydrophobic properties. Explain why the French salad dressing does not separate. You may include a diagram to help you to answer this question. Page 2 (3)

3 Olive oil contains 89% unsaturated fats and % saturated fats. What is the test and the result for unsaturated fats? South Axholme School (2) (c) Olive oil is hardened to make margarine. Describe the reaction and conditions needed to harden a vegetable oil (3) (Total 9 marks) Q3. An advert for crisps claimed that they are healthier because they are cooked in sunflower oil. (a) A student found the following information about four oils that are used to make crisps. Rapeseed oil Sunflower oil Olive oil Corn oil Saturated fat (%) Polyunsaturated fat (%) Melting point ( C) One hypothesis is that oils are thought to be healthier if they are: low in saturated fat high in polyunsaturated fat. (i) Use the table to decide which oil should be healthiest. Explain your decision by comparing this oil with other oils from the table that you think are less healthy. Healthiest oil is... Explanation... (2) Page 3

These oils can be hardened by reacting them with hydrogen. A student said that hardening would make sunflower oil healthier. Is this student s claim correct? Explain your answer.

4 These oils can be hardened by reacting them with hydrogen. A student said that hardening would make sunflower oil healthier. Is this student s claim correct? Explain your answer. South Axholme School (2) A mixture of the olive oil, water and egg yolk was shaken and left to stand. The olive oil and water do not separate. The diagram shows a simple model of how a stable mixture of olive oil and water is produced by the addition of egg yolk. Use this simple model to explain how the molecules in the egg yolk are able to produce a stable mixture of olive oil and water (3) (Total 7 marks) Page 4

5 Q4. Medical evidence suggests that eating saturated fats, compared with unsaturated fats, is associated with a higher risk of circulatory and heart problems. Each of the oils listed in the table contains a mixture of saturated and unsaturated fats. Oil Melting point in C Iodine number palm olive rapeseed sunflower The iodine number is the mass of iodine in grams that reacts with 00 cm 3 of the oil. The iodine number shows the amount of unsaturated fat in each oil. (a) (i) What would be seen if a solution containing g of iodine was added to 00 cm 3 of any of these oils? () What does the word unsaturated mean? () (iii) Which oil in the table would probably cause the highest risk of circulatory and heart problems? Use the information in the table to give a reason for your answer. Oil... Reason (2) Sunflower oil can be hardened so that it can be used to make margarine. Explain how sunflower oil can be hardened (3) (Total 7 marks) Page 5

6 Q5. This question is about plant oils. (a) Steam distillation is used to separate oils from plants. The diagram shows some apparatus that can be used to separate oil from lavender plants. Four parts of the apparatus are labelled W, X, Y and Z. Describe how lavender oil is separated from the plant material. You need to describe what happens in each of the parts, W, X, Y and Z, of the apparatus. (4) Olive oil can be used in the manufacture of margarine. Olive oil has a melting point of 6 C and contains about % saturated fat and 89% unsaturated fat. (i) Describe a test to show that olive oil contains unsaturated compounds. Give the result of the test. (2) To make margarine from olive oil the percentage of unsaturated fat needs to be decreased. Give one reason why. () (iii) Describe how to decrease the percentage of unsaturated fat in olive oil. (3) (Total 0 marks) Page 6

7 M.(a) (i) (vegetable oils) provide energy any two from: crushing pressing distillation. allow filtering, decanting, centrifuging (for either second or third bullet point) 2 vegetable oils have a higher boiling point (than water) allow cooks food at a higher temperature (than water) so foods are cooked faster (than with water) if no other mark awarded allow mark for flavour / texture (c) the emulsifier molecules have a head or hydrophilic end which dissolves in / attracted to water allow a diagram for any of the marking points the emulsifier molecules have a tail or hydrophobic end which dissolves in / attracted to oil allow mark if both attractions are reversed so forms a (stable) suspension or droplets of oil in water or vice versa allow droplets repel each other hydrophilic is the head of the molecule or hydrophobic is the tail of the molecule allow this mark anywhere in the answer [9] M2. (a) (i) olive oil does not dissolve in water accept olive oil and water are immiscible allow there is no emulsifier ignore mustard ignore do not mix / different densities Page 7

8 because mustard is an emulsifier or an emulsion forms or a suspension of oil in vinegar / water forms or vice versa accept because an emulsifier is added South Axholme School the molecules have a head / hydrophilic end which dissolves in / attracted to water and a tail / hydrophobic end which dissolves in / attracted to oil accept a diagram for either or both of these two marking points if diagram contradicts the description or vice versa max one of these two marks (test:) bromine (water) allow iodine (solution) (result:) turns colourless allow orange colour disappears / decolourises ignore clear (c) (olive oil is reacted with) hydrogen accept hydrogenated using a nickel catalyst (at a temperature of about) 60 C allow C ignore hot / heat [9] Page 8

9 M3. (a) (i) (healthiest oil is) sunflower (oil) or rapeseed (oil) sunflower (oil) is healthiest because it has less saturated fat than both olive (oil) and corn (oil) or rapeseed (oil) is healthiest because it has the lowest value of saturated fat compared with the other oils sunflower (oil) is healthiest because it has the highest value of polyunsaturated fat compared with all the other oils or rapeseed (oil) is healthiest because it has more polyunsaturated fat than both olive (oil) and corn (oil) no mark for the choice of oil accept the use of values from the table for these comparisons no, because hydrogen adds to the unsaturated fat or no, because hydrogen reduces the number of carbon carbon double bonds accept no because reacting with hydrogen increases number of single bonds therefore there will be less polyunsaturated fat accept therefore there will be more saturated fat molecules in egg yolk act as emulsifiers accept lecithin molecules act as emulsifiers because molecules in egg yolk have a head which dissolves in / attracted to water accept because molecules in egg yolk are hydrophilic because molecules in egg yolk have a tail which dissolves in / attracted to oil accept because molecules in egg yolk are hydrophobic [7] Page 9

10 M4. (a) (i) (iodine is) decolourised accept colourless allow oil decolourised ignore initial colour of iodine / nothing / clear (molecule / compound) has a double (carbon carbon) bond allow C = C (iii) palm any one from: only allow this mark if correct or no answer in first part ignore references to iodine number / melting point contains less / low amount of unsaturated fat(s) contains more / high amount of saturated fat(s) any three from: cracking / emulsification = max 2 (react with) hydrogen accept by hydrogenation do not accept cracking / emulsify with a (nickel) catalyst at about 60 C allow hot or range 50 C to 20 C increase the melting point 3 [7] Page 0

11 M5. (a) students do not have to use the letters but the descriptions should be in logical order W the water boils or steam is produced allow water vapour rises X the oils / substances (in lavender) are vaporised / removed (by the steam) Y (the vapours are) condensed allow turned back to liquid ignore cooled Z the water can be run off / tapped off leaving the oil(s) allow oil floats on water or they form two layers (i) incorrect reagent = 0 marks add bromine water (bromine water) is decolourised / goes colourless ignore clear if colour of bromine water given it must be yellow, orange, red or brown any one from: to harden the oil to change the oil into a solid to make the oil into a spread to increase its melting point ignore boiling point Page

12 (iii) incorrect process = max 2 (olive oil is) reacted with hydrogen accept hydrogenated using a nickel catalyst at a temperature of about 60 C allow 50 C to 60 C if last two points not given allow heat with a catalyst for mark [0] Page 2

Learning Objectives. Understand the different types and uses of fats and oils in food preparation - functions.

Learning Objectives. Understand the different types and uses of fats and oils in food preparation - functions. FATS AND OILS Learning Objectives Understand the different types and uses of fats and oils in food preparation - functions. Name some of the different fats and oils. Explain how fats shorten pastry. Think