{"id":51,"date":"2014-10-21T07:39:27","date_gmt":"2014-10-21T07:39:27","guid":{"rendered":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu2hwrk\/the-chemistry-of-cooking-and-oxidation-of-food\/"},"modified":"2015-05-20T14:09:09","modified_gmt":"2015-05-20T14:09:09","slug":"the-chemistry-of-cooking-and-oxidation-of-food","status":"publish","type":"page","link":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu2hwrk\/the-chemistry-of-cooking-and-oxidation-of-food\/","title":{"rendered":"Exercise 9a: The Chemistry of Cooking and Oxidation of Food"},"content":{"rendered":"

\"\"<\/a>1. Copy the following carbon skeleton 3 times and add one hydroxyl group to each to make a primary, secondary and tertiary alcohol.
\nWhich of the following alcohols is a tertiary alcohol?<\/p>\n

\"\"<\/a><\/p>\n

2. Draw the structural formulae for each of the following alcohols and state whether the alcohol is a primary, secondary or tertiary alcohol.
\na) Pentan-3-ol. b) 2-methylbutan-1-ol c) 3-ethylpentan-3-ol.
\n3. Compound X is a secondary alcohol.<\/p>\n

\"\"<\/a><\/p>\n

(a) Name compound X.
\n(b) Draw a structural formula for the tertiary alcohol that is an isomer of compound X.
\n4.<\/p>\n

\"\"<\/a><\/p>\n

a) Name the functional group in both molecules.
\nb) To which homologous series does molecule A belong to?
\nc) Name molecule A.
\nd) To which homologous series does molecule B belong to?
\ne) Name molecule B.
\nf) Draw the full structural formula of the molecule which could be oxidised to make molecule A.
\ng) What would be the effect on Benedict\u2019s Solution if it was warmed with B?<\/p>\n

5. What is the general formula for aldehydes and ketones?
\n6. What is the name of the functional group found in aldehydes and ketones?<\/p>\n

\"\"<\/a>7. The compound shown is an example of
\nA a primary alcohol
\nB a secondary alcohol
\nC a tertiary alcohol
\nDan aldehyde<\/p>\n

8. Which of the following is an aldehyde?<\/p>\n

\"\"<\/a><\/p>\n

9. Which of the following compounds is a ketone?<\/p>\n

\"\"<\/a><\/p>\n

10. Which is true of a compound with the following formula?
\nCH3<\/sub>CH(OH)CH3<\/sub>
\nA It is a primary alcohol
\nB It can be oxidised to an aldehyde
\nC It is a tertiary alcohol
\nD It can be oxidised to a ketone.<\/p>\n

11. Look at the diagram and answer the questions that follow.<\/p>\n

\"\"<\/a><\/p>\n

a) What type of alcohol is ethanol?
\nb) Name the type of reaction undergone by the ethanol.
\nc) State the function of the copper(II)oxide.
\nd) The universal indicator changes from green to red. Name the product which causes this change.
\ne) The copper(II)oxide changes from black to brown. Write the ion-electron half equation for this change.
\nf) What change would the copper(II)oxide have shown if the alcohol used had been\u2026\u2026\u2026
\ni) butan-2-ol
\nii) 2-methylbutan-1-ol
\niii) 2-methylbutan-2-ol (3)
\ng) Name another reagent which could have been used instead of Copper(II)oxide.<\/p>\n

12. Which process is used to convert methanol to methanal?
\nA oxidation
\nB condensation
\nC hydration
\nD hydrogenation<\/p>\n

13. Which of the following alcohols can be oxidised to give a ketone?
\nA 2-methylbutan-1-ol
\nB 2,3-dimethylpentan-1-ol
\nC 3-methylbutan-2-ol
\nD 2-methylbutan-2-ol<\/p>\n

14. What colour change happens when acidified dichromate is reduced?<\/p>\n

A Blue to orange
\nB Orange to green
\nC Green to orange
\nD Orange to purple<\/p>\n

15. Oxidation of a primary alcohol produces
\nA an aldehyde
\nB an alkane
\nC a ketone
\nD an alkane<\/p>\n

\"\"<\/a>16. After heating for several minutes as shown in the diagram, the pH indicator solution turned red. Liquid Q could be
\nA propanone
\nB paraffin
\nC butan-1-ol
\nD butan-2-ol<\/p>\n

17. What compound is formed by the oxidation of propan-2-ol?
\nA CH3<\/sub>CH2<\/sub>CHO
\nB CH3<\/sub>CO CH3<\/sub>
\nC CH3<\/sub>CH2<\/sub>COOH
\nD CH3<\/sub>CH2<\/sub> CH2<\/sub>OH<\/p>\n

18. Which of the following would NOT be easily oxidised by acidified dichromate?<\/p>\n

\"\"<\/a><\/p>\n

19. Use this grid to answer the following<\/p>\n

\"\"<\/a><\/p>\n

a) Which molecule is an aldehyde?
\nb) Which molecule is an ketone<\/p>\n

20. During oxidation, what happens to the ratio of O:H atoms in a hydrocarbon?<\/p>\n

21. Although aldehydes and ketones contain the carbonyl functional group, they have different structures.<\/p>\n

(a) In what way is the structure of an aldehyde different from a ketone?
\n(b) Due to the difference in structure only aldehydes react with Benedict\u2019s reagent. What colour change would be observed int he reaction?
\n(c) Name another suitable oxidising agent that could be used in the reaction in place of Benedict\u2019s reagent
\n(d) When butanal is oxidised the compound with the formula C3<\/sub>H7<\/sub>COOH is produced. Name this compound<\/p>\n

22. Two compounds A and B, both have the formula C4<\/sub>H8<\/sub>O. They were both mixed separately with Fehling\u2019s solution and the mixtures warmed in a water bath. Only compound B gave an orange-red precipitate.
\na) Name compounds A and B.
\nb) Draw the extended structural formulae of A and B.
\nc) Name another reagent which could also be used to show the difference between compound A and B and say what would happen when this reagent is reacted with A and B.<\/p>\n

23. Which box, or boxes, show(s) a substance which
\n\"\"<\/a><\/p>\n

a) can be oxidised to an alkanal (aldehyde)?
\nb) is an alkanone (ketone)?
\nc) is an alkanoic (carboxylic) acid?
\nd) is a primary alcohol?
\ne) can be formed by the oxidation of B?<\/p>\n

24. Propan-1-ol, can be oxidised by passing the alcohol vapour over hot copper(II) oxide.
\na) Draw a labelled diagram of the apparatus that would be used to carry out this experiment in the laboratory.
\nb) Oxidation of propan-1-ol yields a compound X, formula C3<\/sub>H6<\/sub>O, which can be further oxidised to compound Y, formula C3<\/sub>H6<\/sub>O2<\/sub>.
\ni) Name and draw the structure of compound X.
\nii) Name and draw the structure of compound Y.
\nc) Name two other oxidising agents which could be used to carry out the oxidation.
\nd) If propan-2-ol was used in place of propan-1-ol there would be only one oxidation product. Name and draw the structure of this product.<\/p>\n

25. “Self-test” kits can be used to check the quantity of alcohol present in a person’s breath.The person blows through a glass tube until a plastic bag at the end is completely filled.
\n\"\"<\/a>
\nThe tube contains orange acidified potassium dichromate crystals that turn green when they react with ethanol. The chemical reaction causing the colour change is:<\/p>\n

\"\"<\/a><\/p>\n

The more ethanol present in the person’s breath, the further along the tube the green colour travels.
\na) What is the purpose of the plastic bag?
\nb) Why are the potassium dichromate crystals acidified?
\nc) Name a carbon compound formed by the reaction of ethanol with acidified potassium dichromate crystals.<\/p>\n

26. Propanone is a widely used solvent. It can be made from propene.
\nUsing full structural formulae show the steps involved in this preparation and name the reagent used in each step.<\/p>\n

27. Alkanols can be oxidised to alkanoic acids.<\/p>\n

\"\"<\/a><\/p>\n

(a) Why can step 1 be described as an oxidation reaction?
\n(b) Acidified potassium dichromate solution can be used to oxidise propanal in step 2 . What colour change would be observed in this reaction?<\/p>\n

28. Two reactions involving a carbon compound, A, are shown.<\/p>\n

\"\"<\/a><\/p>\n

(a) Name compound A.
\n(b)Draw a structural formula for compound B.<\/p>\n

29. Give 3 ways that fatty foods are affected when they react with oxygen.<\/p>\n

30. Chemists have developed cheeses specifically for use in cheeseburgers.
\n(a) When ordinary cheddar cheese is grilled the shapes of the protein molecules change and the proteins and fats separate leaving a chewy solid and an oily liquid.
\nWhat name is given to the change in protein structure which occurs when ordinary cheddar is grilled?
\n(b) To make cheese for burgers, grated cheddar cheese, soluble milk proteins and some water are mixed and heated to no more than 82 \u00b0C. As the cheese begins to melt an emulsifying agent is added and the mixture is stirred.
\n(i) Why would a water bath be used to heat the mixture?
\n(ii) A section of the structure of a soluble milk protein is shown below.<\/p>\n

\"\"<\/a><\/p>\n

Draw a structural formula for any one of the amino acids formed when this section of protein is hydrolysed.
\niii) The emulsifier used is trisodium citrate, a salt formed when citric acid is neutralised using sodium hydroxide.
\nCopy and complete the equation below showing a structural formula for the trisodium citrate formed.<\/p>\n

\"\"<\/a>
\n31. A student closed his eyes and held his nose. Another pupil gave him a teaspoon of strawberry jam to eat. Explain why the student could tell that the food was sweet, but not what the actual flavor was.
\n32. Explain why broccoli should be cooked in water but asparagus should be cooked in oil.<\/p>\n

33. Flavour molecules in different foods are shown below.<\/p>\n

\"\"<\/a><\/p>\n

For each molecule suggest if it should be cooked in oil or water.<\/p>\n","protected":false},"excerpt":{"rendered":"

1. Copy the following carbon skeleton 3 times and add one hydroxyl group to each to make a primary, secondary and tertiary alcohol. Which of the following alcohols is a tertiary alcohol? 2. Draw the structural formulae for each of the following alcohols and state whether the alcohol is a primary, secondary or tertiary alcohol. … Continue reading “Exercise 9a: The Chemistry of Cooking and Oxidation of Food”<\/span><\/a><\/p>\n","protected":false},"author":2454,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"open","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-51","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu2hwrk\/wp-json\/wp\/v2\/pages\/51","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu2hwrk\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu2hwrk\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu2hwrk\/wp-json\/wp\/v2\/users\/2454"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu2hwrk\/wp-json\/wp\/v2\/comments?post=51"}],"version-history":[{"count":13,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu2hwrk\/wp-json\/wp\/v2\/pages\/51\/revisions"}],"predecessor-version":[{"id":190,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu2hwrk\/wp-json\/wp\/v2\/pages\/51\/revisions\/190"}],"wp:attachment":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsechchemu2hwrk\/wp-json\/wp\/v2\/media?parent=51"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}