Organic Chemistry unit formative exam

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1 Class: Date: Organic Chemistry unit formative exam Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Which of the following statements is true about polymers? a. All polymers are macromolecules. b. All polymers are inorganic substances. c. All macromolecules have monomers. d. All polymers have only one kind of monomer. 2. The following structure shows a condensation polymer of polyethylene terephthalate fibres. What type of linkage is present between the monomers? a. Ester linkage c. Halide linkage b. Amide linkage d. Ether Linkage 3. Teflon, an addition polymer, is quite flexible and is resistant to solvents. It remains stable up to 598 K. Such polymers are used as coating in non-stick utensils and gaskets. The structure of this polymer is given by: The monomer unit of this polymer is a. difluoroethane c. diflouroethene b. fluoroethane d. tetrafluoroethene 4. Which of the following reactions is an elimination reaction? a. CH 3 CH 2 C º CH + H 2 à CH 3 CH 2 CH = CH 2 b. C 2 H 5 OH + CH 3 COOH à CH 3 COOC 2 H 5 + H 2 O c. CH 3 CH(OH)CH 3 à CH 3 CH = CH 2 + H 2 O d. CH 3 OH + O 2 à CO 2 + 2H 2 O 1

2 5. The function group in methanol is: a. OH b. c. X (X is a halogen) d. 6. Use the following information to answer the next question. An unsaturated compound is passed into dilute sulfuric acid in the presence of mercury(ii) sulfate as a catalyst, forming the unstable compound ethen 1 ol, CH 2 = COH. This process represents a/an a. addition reaction c. combustion reaction b. substitution reaction d. elimination reaction 7. Use the following information to answer the next question. The compound that contains hydroxyl group as its functional group is a. (i) c. (iii) b. (ii) d. (iv) 2

3 8. The functional group present in the compound below is: a. carboxyl group c. hydroxyl group b. halogen group d. ester group 9. Use the following information to answer the next question. The functional group present in the given structure is a. hydroxyl group c. carboxyl group b. ester group d. alkenyl group 10. Use the following information to answer the next question. The IUPAC name of the given compound is a. pentanoic acid c. propyl methanoate b. butanoic acid d. 2 oxy butan-1-ol 3

4 11. Use the following information to answer the next question. When this compound reacts with an organic compound having a hydroxyl group, in the presence of acidic medium, such a reaction is a/an a. addition reaction c. elimination reaction b. condensation reaction d. substitution reaction 12. Use the following information to answer the next question. In an experiment, cyclohexanol is treated with phosphoric acid at a temperature of 110 o C 160 o C. In this process, a compound x and a water molecule are produced. The functional group present in the product formed in this process is a. carboxyl group c. alkene group b. alkyne group d. hydroxyl group 13. Use the following information to answer the next question. The above structure is an isomer of a. butane c. heptane b. pentane d. hexane 4

5 14. Which of the following structures does not represent an isomer of hexane? a. b. c. d. 15. Use the following information to answer the next question. Four unsaturated compounds W, X, Y and Z, within the same homologous series; the number of carbon atoms increases from W to Z. Which of the given compounds has the lowest boiling point? a. W c. X b. Y d. Z 16. Use the following information to answer the next question. In a chemical experiment, 1, 1, 2, 2- tetrabromoethane is treated with alcoholic zinc to produce an unsaturated substituted hydrocarbon. This process represents an example of a. substitution reaction c. elimination reaction b. addition reaction d. combustion reaction 17. Which of the following carboxylic acids is the least soluble in water? a. CH 3 COOH c. C 3 H 7 COOH b. CH 2 H 5 COOH d. C 4 H 9 COOH 18. The IUPAC name of compound CH 3 C(CH 3 )CHCH 3 is a. 2 methylbut 3 ene c. 2 methylbut 2 ene b. 3 methylbut 2 ene d. 3 methylbut 3 ene 5

6 19. Consider the following structure of a compound: The compound is an isomer of a. propane c. propyne b. propene d. cyclopropene 20. Use the following information to answer the next question. Chloroform (CHCl 3 ) is generally used as an anesthesia in medical treatment. It is also used in the chemical industry to produces dyes and pesticides. It is generally obtained by the action of chlorine on a hydrocarbon in the presence of sun rays. Cl 2 + X à Chloroform If X is the hydrocarbon used for the production for chloroform, compound X is a. methane c. ethane b. ethene d. propyne 21. Use the following information to answer the next question. When compound X reacts with compound Y in an acid, a sweet-smelling compound is produced. When compound X is treated with sulfuric acid, an alkene and water are produced. Compound X is a/an: a. alcohol c. alkyne b. carboxylic acid d. alkane 6

7 22. The structural formula of 2,2,4-trimethylpentane is a. b. c. d. 23. When propene is treated with bromine water, Br 2 (l), in the presence of carbon tetrachloride as a catalyst, the product is: a. 1,2 dibromopropane c. 2 bromopropane b. 2,2 dibromopropane d. 1 bromopropane 24. One of the products formed when pentene reacts with hydrogen bromide, HBr, is 2-bromopentane. What type of reaction is this? a. elimination c. substitution b. addition d. methylation 25. In an experiment, propan-1-ol is made to react with propanoic acid, in the presence of concentrated sulfuric acid as a catalyst. The product is: a. propyl butanoate c. propyl propanoate b. ethyl propanoate d. butyl propanoate 7

8 26. Use the following information to answer the next question. The combustion reaction propene is shown below: ach 3 CH = CH 2 + bo 2 à cco 2 + dh 2 O The respective values of variables a, b, c and d are a. 2, 4, 6, 5 c. 2, 8, 5, 7 b. 3, 4, 3, 6 d. 2, 9, 6, Use the following information to answer the next question. Consider the following additon reaction: CH 3 CH 2 - C º C CH 3 + 2H 2 CH 3 CH 2 CH 2 CH 2 CH 3 The IUPAC name of the first reactant is a. pent 2 yne c. pent 2 ene b. pent 3 yne d. pent 3 ene 28. The IUPAC name of the following organic compound is a. 1, 2-dichlorobenzene c. 1, 5-dibenzochloride b. 1, 3-dichlorobenzene d. 1, 3-dibenzochloride 29. Which of the following molecular structures represents 1,3-dimethylcyclobutane? a. c. b. d. 30. In an organic compound, two methyl groups are found at the third and sixth positions and two double bonds exist at the first and fourth positions. If this compound has a ring structure with minimum possible number of carbon atoms, the IUPAC name of this compound will be a. 3,6-dimethylpent-1,4-diene c. 3,6-dimethylhept-1,4-diene b. 3,6-dimethylhex-1,4-diene d. 3,6-dimethyloct-1,4-diene 8

9 31. The IUPAC name of the molecule is: a. 3-ethyl-2,4,4-trimethylhexane c. 4-ethyl-3,3,5-trimethylhexane b. 3-ethyl-2,4-trimethylhexane d. 4-ethyl-3,5-trimethylhexane 32. Use the following information to answer the next question. Nonane is a saturated hydrocarbon with the empirical formula C 9 H 20. This hydrocarbon can exhibit 35 different isomers. One of these isomers is given below. The IUPAC name of this isomer is a. 6-methylnonane c. 6-methyloctane b. 3-methylnonane d. 3-methyloctane 33. Use the following information to answer the next question. Ethylene glycol acts as antifreeze and is used in automobiles and computers. It is also used for preserving body organs and in the manufacture of capacitors. Its structure is shown below. The IUPAC name of this compound is a. ethanol c. 1-hydroxyethane-1,2-diol b. ethane-1,2-diol d. 2,2-dihydroxyethane-1,2-diol 34. Use the following information to answer the next question. The molecular structure of compound x is given below: This fruit-scented compound is generally used in ice creams and other food stuffs as a flavouring agent. The IUPAC name of compound x is a. propyl ethanoate c. ethyl propanoate b. propane ethanoate d. ethane propanoate 9

10 35. Use the following information to answer the next question. The molecular structure of a compound is given below: The IUPAC name of this compound is a. non-5-yne c. oct-4-yne b. hept-3-yne d. dec-5-yne 36. Use the following information to answer the next question. Cellular respiration, the process used by organisms to obtain energy from food, is a series of organic reactions that produces carbon dioxide, water, and energy. In this process, carbohydrate and fat are oxidized to produce carbon dioxide and water molecules, and energy is released. + à + + Energy Which of the following organic reactions represents this process? a. Addition reaction c. Elimination reaction b. Substitution reaction d. Combustion reaction 37. Use the following information to answer the next question. William treats compound x with concentrated sulfuric acid to produce compound y. In this process, compound x undergoes an elimination reaction. Compound x is also used to manufacture esters, whereas compound y on hydrogenation gives a saturated hydrocarbon. The functional group present in compound x is a. hydroxyl c. ester b. alkenyl d. halogen 38. Use the following information to answer the next question. (ii) How many functional groups are there in compound (ii)? a. One c. Three b. Two d. Four 10

11 39. Which of the following compounds is the most soluble in water? a. CH 3 CH 2 OH c. CH 3 OH b. CH 3 CH 2 CH 2 OH d. CH 3 CH 2 CH 2 CH 2 OH 40. Alkyl halides are hydrocarbons that contain at least one halogen atom. What is the name of this alkyl? a. 2,5-dichloro-1-methylcyclohexane c. 4,6-dichloro-1-methylcylclohexane b. 1,3-dichloro-4-methylcyclohexane d. 1,5-dichloro-2-methylcyclohexane 41. Structural isomers are compounds that have empirical molecular formula and structural formula. The statement above is completed by the information given in a row of the table below: a. the same the same c. the same different b. different the same d. different different 42. Use the following information to answer the next question. Methyl benzoate has a pleasant smell and is used in the perfumery industry. It is soluble in organic solvents and is sometimes used in pesticides because insects are attracted to its scent. Its structure is: a. c. b. d. 11

12 43. Use the following information to answer the next question. Glycerol is a colourless and odourless liquid with a sweet taste. It contains three hydroxyl groups and it is soluble in water. The structure of glycerol is: IUPAC of glycerol is: a. Propane-1,2,3-triol c. Propane-1,2,3-diol b. Propan-1,2,3-oic acid d. Propan-1,2,3-oate 44. Four organic compounds belonging to different functional groups are: Compound 1. Functional group Which of the above given compounds has the highest boiling point? a. 1 c. 3 b. 2 d Use the following information to answer the next question. An compound has a molecular formula CH 3 CH 2 COOH. It is produced from ethyl alcohol and carbon monoxide. What is the name of the acid? a. Ethanoate c. Propanoic acid b. Ethanoic acid d. Propanol 12

13 46. Two isomers of C 4 O 2 H 8 are: and The names of both these compounds are a. methyl propanoate and propyl methanoate b. propyl methanoate and methyl methanoate c. propyl propanoate and methyl propanoate d. propyl methanoate and methyl propanoate 47. An organic compound with the molecular formula C 3 H 7 Br(l) is a colourless liquid used in organic synthesis. The structure of the compound is: What is the name of the compound? a. Bromopropane c. 2-Bromopropane b. Bromoprop-2-ane d. 2-Propanebromide 48. Use the following information to answer the next question. Organic compounds are classified according to the functional group as 1. Alcohol 2. Alkyl 3. Carboxylic acid 4. Ester Of the above four organic families, compounds i and ii are capable of forming hydrogen bonds. The statement given above is completed by the information given in the row: Row i ii A 1 2 B 2 3 C 3 4 D 2 4 a. A c. C b. B d. D 13

14 49. Use the following information to answer the next question. In an experiment, ethyl bromide is treated with KOH to give an organic compound z. This above reaction is a type of a/an a. substitution reaction c. elimination reaction b. addition reaction d. esterification reaction 50. Use the following information to answer the next question. A scientist treated propene with bromine in the presence of carbon tetrachloride. The results was 1,2-dibromoprapane. This above reaction is a type of a/an a. elimination reaction c. combustion reaction b. addition reaction d. substitution reaction 51. Consider the following organic reactions: 1. C 6 H 14 (l) + HNO 3 (l) C 6 H 13 NO 2 (l) + H 2 O(l) 2. CH 4 (g) + 2O 2 (g) CO 2 (g) + 2H 2 O(g) 3. C 2 H 2 Br 4 (l) + 2Zn(s) HCºCH(g) + 2ZnBr 2 (aq) 4. CH 3 COOH(l) + C 2 H 5 OH(l) CH 3 COOC 2 H 5 (l) + H 2 O(l) Which of these reactions represents a combustion reaction? a. 1 c. 3 b. 2 d Name the following compound. a. 4-ethyl-3-methylheptane c. 3-propyl-4-methylhexane b. 4-methyl-3-propylhexane d. 4-ethyl-3-methylhexene 14

15 Numeric Response 53. A functional group is a special arrangement of atoms that is mainly responsible for the chemical behaviour of a molecule. Several functional groups are given below: C º C 4. The correct order of the above functional groups, such that they represent the hydroxyl group, alkanes, alkynes, and alkenes, respectively, is,,, and. 54. An alcohol is a hydrocarbon derivative with the functional group OH. Several structural formulae are given below: Number 1. Structural Formula 2. HO CH 2 CH 2 OH 3. CH 3 CH 2 OH 4. CH 3 OH The correct order of the structural formulae corresponding to the names ethanol, propane-2-ol, methanol, and ethan-1,2-diol, respectively, is,,, and. 15

16 55. Alkyl halides are hydrocarbons containing halogen atoms. The structural formulae of several alkyl halides are given below The correct order of the structural formulae, such that they represent the names bromobenzene, 1,3-dibromo-4-methylcyclohexane, 1-bromo-2-methylbenzene, and 1,3-dibromo-5-methylhexane, respectively, is,,, and. 16

17 56. Chemists use many different reactions to synthesize specific organic products. Reactions are classified into four categories: addition, elimination, combustion, and substitution reactions. Several reactions are shown below The correct order of the reactions, such that they represent an elimination reaction, an addition reaction, a combustion reaction, and a substitution reaction, respectively, is,,, and. 17

18 57. Use the following information to answer the next question. Organic reactions can be classified into four categories: addition, elimination, combustion, and substitution reactions. Each reaction transforms an organic compound into other organic and/or inorganic compounds. 1. Atoms are removed from an organic molecule, and double bonds form between two carbon atoms. 2. A compound reacts with oxygen to produce the oxides of the elements that make the compound. 3. In alkenes and alkynes, atoms are added to double or triple bonds. 4. A hydrogen atom or functional group is replaced by a different functional group The correct order of the definitions, such that they represent an elimination reaction, substitution reaction, combustion reaction, and addition reaction, respectively, is,, and. 18

19 Organic Chemistry unit formative exam Answer Section MULTIPLE CHOICE 1. A It is true that all polymers are macromolecules, but not all macromolecules are not polymers. For example: Chlorophyll, a green pigment in the plants, is a macromolecule. However, it is not a polymer, because it does not contain a repeating monomer unit. 2. A 3. D The monomer unit of teflon is tetrafluoroethene, F 2 C = CF 2. The polymerization reaction of teflon is given by 4. C The following reaction is an elimination reaction as a double bond is produced. CH 3 CHOHCH 3 à CH 3 CH = CH 2 +H 2 O 5. A Alcohols are characterized by the OH functional group. 6. A The given process is an example of an addition reaction and the unsaturated hydrocarbon is ethyne, CH º CH. 7. A 8. D The second compound is an ester, because it has ester linkage. 9. C The given compound contains carboxyl group. 1

20 10. B The given structure can also be represented as Since there are four carbon atoms and a carboxyl group, the IUPAC name of the compound is butanoic acid. 11. B Since the given compound contains a carboxyl group, it is a carboxylic acid. The organic compound that contains a hydroxyl group is an alcohol. When a carboxylic acid reacts with an alcohol in the presence of concentrated sulfuric acid an ester is formed. R' (aq) + H 2 Therefore, it is an esterification reaction. Since a water molecule is eliminated from the given reaction, the given reaction may also be called a condensation reaction. 12. B The above process can be represented by a chemical reaction in the following way: In this reaction, a water molecule is eliminated from the cyclohexanol, and cyclohexene is formed. The functional group present in cyclohexene is an alkene group. 13. C The given structure is It represents an isomer of heptane. In isomers, the number of carbon atoms always remains the same. Since there are seven carbons in the above structure, it represents an isomer of heptane. 14. D 15. A W has the lowest boiling point, because the boiling point of alkenes and alkynes increases with the increase in the number of carbon atoms. W has the lowest boiling point and Z has the highest boiling point. 2

21 16. C This process represents an example of elimination reaction because four bromine atoms are eliminated from the molecule. 17. D The larger the alkyl portion (carbon tail) of the carboxylic acid, the lower the solubility, since the alkyl portion is non-polar. C 4 H 9 COOH is least soluble in water because of its larger non-polar alkyl portion. 18. C The compound used in the given process is According to IUPAC rules of naming the organic compounds, the name of the compound is 2-methyl but 2 ene. 19. B Cyclopropane is an isomer of propene, CH 3 CH = CH 2. The number of carbon and hydrogen atoms is the same in both cyclopropane and propene. 20. A Chloroform is produced when chlorine molecules attack methane gas in the presence of the sun s rays. Cl 2 + CH 3 Cl + HCl CH 3 Cl + Cl 2 CH 2 Cl 2 + HCl CH 2 Cl 2 + Cl 2 + HCl Compound X is methane. 21. A From the given information, the compounds X and Y react with each other to produce an ester (a sweet-smelling compound). Therefore, these compounds are an alcohol and a carboxylic acid. When treated with sulfuric acid, compound X produces an alkene and water, therefore, compound X is an alcohol 22. A The structural formula of 2,2,4-trimethylpentane is. 3

22 23. A When propene reacts with bromine water, Br 2 (l), in the presence of carbon tetrachloride as a catalyst, the addition reaction between propene and bromine molecule takes place, to form 1,2 dibromopropane. CH 2 = CH CH B 25. C When propanol reacts with propanoic acid, in the presence of concentrated sulfuric acid, 26. D When propane burns amidst sufficient supply of air, it gives carbon dioxide and water. The required chemical equation for this process is 2C 3 H 6 (g) + 9O 2 (g) à 6CO 2 (g) + 6H 2 O (g) Therefore, the values of a, b, c and d are: 2, 9, 6 and A The triple bond is attached to the second and third carbon atoms. According to IUPAC rules for naming organic compounds, the bond is named for the second carbon atom. Therefore, the IUPAC name of the compound is pent-2-yne. 28. B The IUPAC name of the given compound is 1,3-dichlorobenzene, because one chlorine atom is attached to the first carbon atom and other one is attached to the third carbon atom. 29. A Since the given compound is an alkane, it should not have any multiple bonds. The numbering starts from one side chain so that the other side chain gets the lowest number. 4

23 30. B As per the information, the compound will look like 31. A The given structure is The parent chain is outlined. On the chain are 4 branches, 3 methyl groups and an ethyl group. Using the smallest numbers possible, the ethyl group is given #3, and the methyl groups are on carbons 2 and 4. Put together, the name is 3-ethyl-2,4,4-trimethylhexane 32. D 33. B The structural formula of ethylene is given as following: HO CH 2 CH 2 OH It is clear from the above structure that the IUPAC name of ethylene glycol is ethane-1,2-diol. 34. C The structure of the compound x is According to the IUPAC rules for naming organic compounds, the IUPAC name of compound x is ethyl propanoate. 35. D According to IUPAC rules for naming compounds, the IUPAC name of the given compound is dec-5-yne. 5

24 36. D Cellular respiration represents a combustion reaction because it involves the production of carbon dioxide and water molecules along with release of energy. 37. A Compound x is used to manufacture esters. Since alcohols and carboxylic acids are used for this purpose, the functional group present in the compound x is the hydroxyl group. 38. B There are two functional groups in compound (ii): alkenyl and carboxyl. 39. C Short-chain molecules containing polar carbon oxygen bonds can form more hydrogen bonds than can longer-chain molecules. As the length of the carbon chain increases, the number of non-polar bonds increases, and the effect of hydrogen bonding becomes less significant, while London (dispersion) forces that act between molecules becomes significant. As the effect of hydrogen bonding decreases, the solubility decreases. 40. B 1,3-dichloro-4-methylcyclohexane 41. C 42. A 43. A There are three carbon atoms in a chain, so its root name is propane. It has three hydroxyl groups on each carbon atom. So its IUPAC name is propane-1,2,3-triol. 44. C The presence of C=O and OH group make the carboxyl group very polar, which allows for hydrogen bonding. Thus, the boiling point of compound 3 (carboxylic acid) is much higher than others. Compound 1 is an alcohol, and its boiling point is higher than compounds 2 and 4 because of hydrogen bonding. Compound 4 is an ester and it cannot form hydrogen bonds. Hence, the boiling point of compound 3 is the highest. 45. C The name of CH 3 CH 2 COOH is propanoic acid. 46. A 47. B 48. D 49. C It is clear that this is an elimination reaction because it involves the removal of the bromide from the reactant. 50. B 51. B A combustion reaction involves the reaction of a hydrocarbon with oxygen gas. In this process, carbon dioxide and water molecules are released along with heat energy. 52. A NUMERIC RESPONSE Alkanes have C C single bonds, alkenes have C = C double bonds, alkynes have C º C triple bonds, and the OH group is the hydroxyl group. 6

25 When one OH group is attached to a methyl group, the structure is called methanol. When two alkane carbons and two OH groups are attached together; the structure is called ethan-1,2-diol. When a three-alkane-carbon chain and one OH group are attached together, and the OH group is attached to the carbon at the second position, the structure is called propane-2-ol. If two alkane carbons and one OH group are attached together, the structure is called ethanol Compounds 1 and 2 are cyclohexane with two bromine atoms and one methyl group.. Numbering begins at a bromine atom and proceeds towards the second bromine and then methyl group. In compounds 3 and 4, the parent compound is benzene, and the numbering starts from benzene and then proceeds towards the methyl group In combustion reactions, hydrocarbons burn completely to yield CO 2 and water vapour. In addition reactions, atoms are added to a double or triple bond. In elimination reactions, atoms are removed from an organic molecule, and a double bond forms between the two carbon atoms from which the atoms were removed.. In substitution reactions, a hydrogen atom or a functional group is replaced by a different functional group