NY Chemistry Regents Multiple Choice Questions Practice With Solutions : ORGANIC CHEMISTRY
January 2023
20 Which formula represents a hydrocarbon?
(1) C2H6 (2) C2H5OH
(3) C2H5Cl
(4) C2H6O
Solution: A hydrocarbon is a molecule that consists of carbons and hydrogens only.
Answer: 1
21 Which statement describes the bonding in an alkyne molecule?
(1) There is at least one carbon-to-carbon double bond.
(2) There is at least one carbon-to-carbon triple bond.
(3) There is at least one carbon-to-oxygen single bond.
(4) There is at least one carbon-to-oxygen double bond.
Solution: According to Table Q on the Reference table, an alkyne molecule has a carbon-to-carbon triple bond.
Answer: 2
22 Which compound has a functional group that contains two oxygen atoms?
(1) 1-propanamine
(2) 2-chloropropane
(3) methyl propanoate
(4) methyl ethyl ether
Solution: We need to look at Table R on the Reference Table. It has functional groups as well as examples of molecules and names. An ester has two oxygens in its functional group. The example of an ester naming is methyl propanoate in the chart.
Answer: 3
23 Which term identifies a type of organic reaction? (1) deposition
(2) distillation
(3) polymerization
(4) vaporization
Solution: Polymerization is a type of organic reaction. Deposition is a phase change from gas to solid. Vaporization is a phase change from liquid to gas. Distillation is a laboratory technique that separates liquids based on their boiling point.
Answer: 3
49 Which formula represents 2-butene?
Solution: Table P and Table Q on the Reference Table represent naming hydrocarbons. The ending "ene" represents that the molecule has a double bond. Choices 3 and 4 can be eliminated. Number 2 represents the carbon to which the double bond is attached. In choice 2, double bond starts at carbon 2 while in choice 1 it starts at carbon number 1.
Answer: Choice 2 is the correct answer choice.
50 Given a formula representing a compound:
Which formula represents an isomer of the compound?
Solution: Isomers are molecules that have the same molecular formula but different structure. The formula for the compound is C3H8O. Compound 1 has the same formula but different structure and is therefore the correct answer choice.
August 2022
46 Given the formula representing a compound:
What is a chemical name for the compound?
(1) 2-chloropentene (2) 2-chloropentane (3) 4-chloropentene (4) 4-chloropentane Explanation: The structure of the molecules has carbons and hydrogens representing an organic molecules. We see all single bonds which means this is an alkane. The name must end in "ane", eliminating choices 1 and 3. Next, we find the longest carbon chain. In this case, it is five carbons. Table P on the reference table shows that the prefix for five carbons is pent, making the parent chain pentane. Finally, we number the carbons from the end closest to chlorine, from the right. Chlorine is on the second carbon from the right and the molecule should be named 2-chloropentane. Answer: 2
47
Which formula represents a saturated organic compound?
(1) C2H2
(2) C2H4
(3) C3H4
(4) C3H8
Explanation: We need to take a look at Table Q on the Reference Table. It has alkanes, alkenes and alkynes and the general formula for each one. Alkanes are saturated organic compounds. Alkenes and alkynes are unsaturated because they have double and triple bonds. The formula for alkanes is CnH2n+2. Let's see which answer choice will work. We plug in the number of carbons in the formula as n to see how many hydrogens we would have, 2n+2. For 2 carbons, we should have 2(2)+2= 6 hydrogens (C2H6) For 3 carbons we should have 2(3)+2 = 8 hydrogens (C3H8).
Answer: 4
48 The compounds CH3CH2CH2OH and CH3OCH2CH3 have different
(1) numbers of carbon atoms per mole
(2) numbers of hydrogen atoms per mole
(3) functional groups
(4) molecular masses
Explanation: Let's take a look at the two molecules. If we count the number of carbons, hydrogens and oxygens, we can see that they both have the same number of each eliminating answer choices 1,2,and 4. CH3CH2CH2OH has an alcohol function group (OH) which can be found in the Table R on the Reference Table. CH3OCH2CH3 has an ether functional group (-O-).
Answer: 3
June 2022
24 Which element must be present in an organic compound?
(1) carbon
(2) sulfur
(3) nitrogen
(4) oxygen
Explanation: Carbon must be present in order for a compound to be considered organic.
Answer: 1
25 Which formula represents a saturated hydrocarbon?
(1) C2H2
(2) C2H4
(3) C6H10
(4) C6H14
Explanation: Saturated hydrocarbons have single bonds only and belong to the alkane family. According to Table Q on the Reference Table, alkanes have a formula of CnH2n+2. Let's now see which of the answer choices correspond to this formula. For 2 carbons, we must have 2(2)+2 = 6 hydrogens. We can eliminate choices 1 and 2. For 6 carbons, we must have 2(6)+2= 14 hydrogens.
Answer: 4
45 Given the formula for a compound:
What is the IUPAC name of the compound?
(1) 2,3-dimethyloctane
(2) 2,3-dimethylhexane
(3) 4,5-dimethyloctane
(4) 4,5-dimethylhexane
Explanation: First we need to find the longest continuous carbon chain (parent chain) . The longest chain of carbons is the horizontal chain and it has 6 carbons. According to Table P on the Reference Table, 6 carbons should have a prefix hex and since it is all single bonds the parent's chain should be named hexane. Choices 1 and 3 can be eliminated.
Next, we count the carbons on the parent chain starting from the end that is closest to the first attachment.
Next, we name the groups attached. Both groups have one carbon and according to Table P should have a prefix meth. We get 2- methyl (CH3 attached to carbon 2) and 3- methyl (CH3 attached to carbon 3). Combining all-together we get 2,3-dimethylhexane .
46 Given the formula representing a compound:
This compound is classified as an (1) amide (2) amine
(3) ester
(4) ether
Explanation: We need to take a look at Table R on the Reference table which lists the classes of organic compounds together with their functional groups. The functional group for this molecule is carbon attached to oxygen and NH2. This is the functional group for amide.
Answer: 1
January 2020
20 Given the organic functional group:
Which class of organic compounds has molecules with this functional group? (1) aldehydes (2) esters
(3) ketones
(4) organic acids
Solution: We need to take a look at Table R on the Reference table which lists the classes of organic compounds together with their functional groups. This molecule is an aldehyde.
Answer: 1
18 Which organic prefix is matched with the number of carbon atoms that it represents? (1) hept-, 7
(2) non-, 8
(3) pent-, 3
(4) prop-, 4
Solution: According to Table P on the Reference Table, hept is the correct prefix for 7 carbons.
Answer: 1
43 Given the formula for a compound:
What is a chemical name for the compound? (1) 1-butanamine
(2) 1-butanol (3) butanamide
(4) butanoic acid
Solution: We need to take a look at Table R on the Reference table which lists the classes of organic compounds together with their functional groups. This functional group is for an amide. The parent chain has 4 carbons, which means the prefix needs to be but according to Table P.
Answer: Butanamide is the correct answer.Choice 3
August 2019
22 The only two elements in alkenes and alkynes are (1) carbon and nitrogen
(2) carbon and hydrogen
(3) oxygen and nitrogen
(4) oxygen and hydrogen
Solution: Table Q on the Reference Table shows Homologous Series of Hydrocarbons which includes alkenes and alkynes. The name hydrocarbon comes from hydrogens and carbon. These are the only two elements found in these molecules.
Answer: 2
23 Which functional group contains a nitrogen atom and an oxygen atom?
(1) ester
(2) ether (3) amide
(4) amine
Solution: We need to take a look at Table R on the Reference table which lists the classes of organic compounds together with their functional groups. An amide has both an oxygen atom and a nitrogen atom.
Answer: 3
45 Given the formula for a compound:
What is the name of this compound?
(1) methyl butanoate
(2) methyl butyl ether (3) pentanone (4) pentanoic acid
Solution: We need to take a look at Table R on the Reference table which lists the classes of organic compounds together with their functional groups. The functional group here is that of an ester. The example of the molecule given in Table R for an ester is almost the same as the molecule in our question, except the parent chain is one carbon longer. The ending for an ester is "oate".
Answer: 1
June 2019
25 What is the general formula for the homologous series that includes ethene?
(1) CnH2n
(2) CnH2n+6
(3) CnH2n+2
(4) CnH2n+2
Solution: Ethene ends in "ene" which means it is an alkene. Table Q on the Reference Table shows the correct formula for alkenes, CnH2n
Answer: Choice 1 is correct
45 Given the formula representing a molecule:
A chemical name for this compound is (1) pentanone (2) 1-pentanol
(3) 1-pentanamine
(4) pentanamide
Solution: We can look at Table R on the Reference Table. The functional group here is NH2, which is an amine. Example of the name is given on the right.
Answer: Choice 3
46 Given the formula of a compound:
This compound is classified as an
(1) aldehyde (2) alkene (3) alkyne (4) alcohol Solution: Table Q on the Reference Table shows hydrocarbons. The hydrocarbon that has a triple bond in an alkyne. Answer: Choice 3
January 2019
23 Which compound is saturated? (1) butane
(2) ethene
(3) heptene
(4) pentyne
Solution: Table Q on the Reference Table shows Homologous Series of Hydrocarbons which includes alkanes, alkenes and alkynes. Alkanes are considered saturated while alkenes and alkynes are considered unsaturated. Alkanes end in "ane."
Answer: 1
43 Given the formula for a compound:
What is a chemical name for this compound? (1) 1-butanamide
(2) 4-butanamide
(3) 1-butanamine
(4) 4-butanamine
Solution: We can look at Table R on the Reference Table. The functional group here is NH2, which is an amine. Example of the name is given on the right. There are 4 carbons. Prefix for 4 is but according to Table P. NH2 is on the first carbon, making the name 1-butanamine.
Answer: Choice 3
44 Given the equation for a reaction: C4H10 + Cl2 → C4H9Cl + HCl Which type of reaction is represented by the equation? (1) addition
(2) substitution
(3) fermentation
(4) polymerization
Solution: In this reaction hydrogen is substituted by chlorine if we look from the left side (reactants) to the right side (products). This reaction is substitution. Generally, if we see an alkane (CnH2n+2 with X2, where X is halogen), the reaction is substitution.
Answer : 2
August 2018
21 Amines, amides, and amino acids are categories of (1) isomers (2) isotopes (3) organic compounds
(4) inorganic compounds
Solution: Amines, amides and amino acids are all organic compounds.
Isomers are molecules with the same formula but different structure. Isotopes are atoms of the same element with different mass.
Answer: 3
22 A molecule of which compound has a multiple covalent bond?
(1) CH4
(2) C2H4 (3) C3H8
(4) C4H10
Solution: Table Q on the Reference Table shows Homologous Series of Hydrocarbons. We can see that alkenes and alkynes have multiple covalent bonds (double bond for alkenes and triple bond for alkynes). The formula for alkenes is CnH2n. C2H4 represents an alkene. The rest of the formulas are for alkanes, CnH2n+2
Answer: 2
23 Which type of reaction produces soap?
(1) polymerization
(2) combustion (3) fermentation
(4) saponification
Solution: Saponification is a reaction that produces soap.
Answer: 4
44 What is the chemical name for the compound CH3CH2CH2CH3?
(1) butane
(2) butene (3) decane
(4) decene
Solutions: Table Q on the Reference Table shows hydrocarbons. This hydrocarbon has all single bonds and therefore, must be an alkane. Alkane names end in "ane", eliminating choices 2 and 4. Next, we can count the number of carbons in the compound, which is 4. Table P shows the prefixes for the carbon chains. The prefix for a chain of 4 carbons in "but". Butane must be the name for the compound presented.
Answer: 1
January 2018
20 Which formula represents an alkyne?
(1) CnHn
(2) C2nHn
(3) CnH2n + 2
(4) CnH2n – 2
Solution: Table Q on the Reference Table shows Homologous Series of Hydrocarbons. It shows names and general formula. The formula for an alkyne is CnH2n – 2
Answer: 4
45 Which compounds are isomers of each other? (1) methanol and methanal (2) propanoic acid and pentanoic acid (3) 1-propanol and 2-propanol (4) 1-chloropropane and 2-bromopropane
Solution: Isomers are molecules with the same formula but different structure. We can look at Table R on the reference table which shows functional groups and examples of names with the correct ending. Table P shows the correct prefix for the number of carbons in a chain. We can eliminate choice 4 because one molecule has chlorine and another bromine. We can also eliminate choice 2 because prop means 3 carbons and pent mean 5 carbons. We can eliminate choice 1 because methanol(alcohol) has all single bonds and methanal (aldehyde) has a =O.1-propanol and 2-propanol are isomers of each other because they have the same formula (same number of carbons, hydrogens and oxygens) but different connection. In 1-propanol, the OH group is attached to carbon 1 while in 2-propanol, it is attached to carbon 2.
Answer: 3
46 A reaction between an alcohol and an organic acid is classified as (1) esterification
(2) fermentation
(3) saponification
(4) substitution
Solution: Esterification is a reaction between an alcohol and an organic acid that produces an ester.
Answer: 1
June 2018
21 Which formula can represent an alkyne? (1) C2H4
(2) C2H6
(3) C3H4
(4) C3H6
Solution: Table Q on the Reference Table shows Homologous Series of Hydrocarbons. It shows names and general formula. The formula for an alkyne is CnH2n – 2. If we take a look at C3H1, n=3. 3*2-2 = 6-2=4. It is an alkyne
Answer: 3
22 Given the formula representing a compound:
Which formula represents an isomer of this compound?
Solution: Isomers are molecules with the same formula but different structure. The molecule given has 4 carbons and 10 hydrogens. This eliminates choices 1 and 3 since they have the wrong number of hydrogens. Choice 4 is the same molecule a the one that is given in terms of connection. Choice 2 is the isomer of the compound given.
Answer: 2
45 Which equation represents an addition reaction?
(1) C3H8 + Cl2→ C3H7Cl +HCl (2) C3H6 + Cl2 → C3H6Cl2 (3) CaCl2 + Na2CO3 → CaCO3 + 2NaCl
(4) CaCO3→ CaO + CO2
Solution: An addition reaction starts with an alkene (formula CnH2n) and reacts with Br2 or Cl2. In choice 2 we can see that we start with an alkene and react with Cl2.
Answer: 2
June 2017
25 What is the name of the compound with the formula CH3CH2CH2NH2? (1) 1-propanol (2) 1-propanamine
(3) propanal
(4) propanamide
Solution: We can look at Table R on the Reference Table. The functional group here is NH2, which is an amine. Example of the name is given on the right. There are 3 carbons. Prefix for 3 is "prop" according to Table P. NH2 is on the first carbon, making the name 1-propanamine
Answer: 2
26 Which compound is an isomer of C2H5OC2H5? 1) CH3COOH
(2) C2H5COOCH3
(3) C3H7COCH3
(4) C4H9OH
Solution: Isomers are molecules with the same formula but different structure. The compound given has 4 carbons, 10 hydrogens and 1 oxygen. Choices 1 and 2 can be eliminates since they have 2 oxygens. Choice 3 has 5 carbons and can be eliminated as well. Choice 4 has 4 carbons, 1 oxygen and 10 hydrogens.
Answer: 4
27 Ethanoic acid and 1-butanol can react to produce water and a compound classified as an (1) aldehyde
(2) amide
(3) ester
(4) ether
Solution: Esterification is a reaction between an alcohol and an organic acid that produces an ester.
Answer: 3
44 Which compound is classified as an ether? (1) CH3CHO
(2) CH3OCH3 (3) CH3COCH3
(4) CH3COOCH3
Solution: We can look at Table R on the Reference Table which shows functional groups. An ether is has a functional group of an oxygen in between two carbons, -O-. This is choice 2. Choice 1 is an aldehyde (CHO). Choice 4 is an ester (COOC). Choice 3 is a ketone ( COC). This one is tricky but it is helpful to draw it out, keeping in mind that every carbon wants 4 bonds.
Answer: 2
June 2016
22 What is the number of electrons shared in the multiple carbon-carbon bond in one molecule of 1-pentyne? (1) 6
(2) 2
(3) 3
(4) 8
Solution: Pentyne ends in "yne", reprising alkynes as can be seen in Table Q on the Reference Table. Alkynes have a triple bond. Each bond has 2 electrons. There are 3 bonds, making it 3*2 = 6 electrons shared.
Answer: 1
23 Butanal, butanone, and diethyl ether have different properties because the molecules of each compound differ in their (1) numbers of carbon atoms
(2) numbers of oxygen atoms
(3) types of functional groups
(4) types of radioactive isotopes
Solution: We can look at Table R on the Reference Table which shows functional groups. Butanal is an aldehyde (from the ending of the name "al"). Butanone is a ketone. Diethyl ether is an ether.
Answer: 3
45 Which hydrocarbon is saturated? (1) C2H2
(2) C3H4
(3) C4H6
(4) C4H10
Solution: Alkanes are saturated hydrocarbons (all single bonds). Table Q on the Reference Table shows the formula for alkanes is CnH2n+2. If we look at choice 4, there are 4 carbons. For 4 carbons there must be 2*4+2 = 10 hydrogens. Choice 4 is an alkane.
Answer: 4
47 Given the formula for an organic compound:
What is the name given to the group in the box?
(1) butyl
(2) ethyl
(3) methyl
(4) propyl
Solution: Table P on the Reference Table shows the prefix for the number of carbons. There are two carbons in a chain that is boxed. The prefix for two carbons is "eth". Choice 2 is the correct answer choice.
Answer: 2
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