Download CLEP Chemistry - Problem Drill 23: Descriptive and Organic

CLEP Chemistry - Problem Drill 23: Descriptive and Organic Chemistry
Question No. 1 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
1. AgNO3 (aq) + KCl (aq) Æ ?
Question
(A) A
(B) A
(C) A
(D) A
(E) A
colorless solution with a colored precipitate.
colorless solution with a white precipitate.
colored solution with no precipitate.
colorless solution with no precipitate.
solution with no precipitate and a gas evolved.
A. Incorrect!
There will be a precipitate, but it will not be colored.
B. Correct!
KNO3 is a colorless solution and AgCl is a white precipitate.
C. Incorrect!
KNO3 is a colorless solution.
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D. Incorrect!
There will be a precipitate.
E. Incorrect!
There will not be any gas produced.
This reaction will be double replacement—two ionic compounds reacting together in
aqueous environment.
AgNO3 (aq) + KCl (aq) → AgCl + KNO3
All nitrates are soluble—KNO3 will be in solution.
Cl-1 is not soluble with Ag+--it will be a precipitate.
KNO3 is not a colored compound—the solution will be colorless.
AgCl is a white precipitate.
Solution
The correct answer is (B).
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Question No. 2 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
2. When NaOH solution is added to which of the following will a white precipitate
form and then re-dissolve?
Question
(A) Al+3
(B) Cr2O7-2
(C) Mg+2
(D) NH4+
(E) Ni+2
A. Correct!
Aluminum forms a soluble complex with hydroxide.
B. Incorrect!
Sodium dissolves with everything, so it will not form a precipitate initially with
dichromate.
C. Incorrect!
Magnesium does not form a complex with hydroxide.
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D. Incorrect!
Ammonium is soluble with hydroxide.
E. Incorrect!
Nickel will not form a complex with hydroxide.
As a cation, Na+ dissolves with everything. So it will not precipitate with “B” the
dichromate.
Which of the cation choices forms a precipitate and then re-dissolves as a complex
with OH-1? Al+3
The correct answer is (A).
Solution
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Question No. 3 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
3. Which organic compound is a weak electrolyte?
Question
(A) C2H6
(B) CH3Cl
(C) HCOOH
(D) CH3OH
(E) C6H12O6
A. Incorrect!
Hydrocarbons do not dissociate.
B. Incorrect!
Halo-hydrocarbons do not dissociate.
C. Correct!
Carboxylic acids do dissociate slightly.
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D. Incorrect!
Alcohols do not dissociate.
E. Incorrect!
Sugar will not dissociate.
In order to be a weak electrolyte, some ions must form.
A common organic weak electrolyte is a carboxylic acid (-COOH). The weak acid
dissociates some protons, leaving behind the anion. Therefore, some ions are
produced.
The correct answer is (C).
Solution
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Question No. 4 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
4. In the complete combustion of propane, the products are:
Question
(A) water and carbon
(B) propanone and water
(C) propanoic acid and water
(D) carbon dioxide and water
(E) carbon dioxide and oxygen
A. Incorrect!
Carbon is a reactant in some combustions, not a product.
B. Incorrect!
Propanone is not a product of combustion.
C. Incorrect!
Propanoic acid is not a product of combustion.
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D. Correct!
Carbon dioxide and water are the products of hydrocarbon combustions.
E. Incorrect!
Oxygen is a reactant in combustion, not a product.
Propane is a hydrocarbon (only carbon and hydrogen present). When a
hydrocarbon is combusted (reacted with oxygen), the products are carbon dioxide
and water.
The correct answer is (D).
Solution
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Question No. 5 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
5. Which of the following is a structural isomer for CH3-CH2-CH2-CH3?
Question
(A) CH3-CH(CH3)-CH3
(B) CH3-CH=CH-CH3
(C) CH2=CH-CH=CH2
(D) All of the above
(E) None of the above
A. Correct!
Structural isomers have the same chemical formula, but different chemical
structure.
B. Incorrect!
This is not a structural isomer—different formula.
C. Incorrect!
This is not a structural isomer—different formula.
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D. Incorrect!
Only one of them is a structural isomer.
E. Incorrect!
One of them is a structural isomer.
Structural isomers are two molecules with the same chemical formula, but a
different bonding structure.
Options B & C both have a different chemical formula than the original molecule.
The correct answer is (A).
Solution
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Question No. 6 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
6. CuCl2 (aq) + NaOH (aq) Æ ?
Question
(A) A
(B) A
(C) A
(D) A
(E) A
colorless solution with a precipitate.
colorless solution without a precipitate.
colored solution with precipitate.
colored solution without precipitate.
solution with no precipitate and a gas evolved.
A. Correct!
There will be a precipitate with a colorless solution.
B. Incorrect!
The solution will be colorless, but there will be a precipitate.
C. Incorrect!
NaCl is a colorless solution.
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D. Incorrect!
NaCl is a colorless solution.
E. Incorrect!
There will not be any gas produced.
This reaction will be double replacement—two ionic compounds reacting together in
aqueous environment.
CuCl2 (aq) + 2 NaOH (aq) → Cu(OH)2 + 2 NaCl
NaCl is a colorless solution.
Cu(OH)2 forms a gelly-like precipitate.
The correct answer is (A).
Solution
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Question No. 7 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
7. A complex ion is:
Question
(A) An insoluble compound formed from soluble compounds.
(B) A neutral combination of cation and anion.
(C) An ion surrounded by ligands that is soluble.
(D) An ion that dissolves in some solutions and not in others.
(E) None of the above.
A. Incorrect!
This is the definition of precipitate.
B. Incorrect!
This is the definition of an ionic compound.
C. Correct!
A complex ion is --- “an ion surrounded by ligands that is soluble.”
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D. Incorrect!
Look again for a correct definition.
E. Incorrect!
There is a definition for complex ion in the choices.
A complex ion is --- “an ion surrounded by ligands that dissolves in water”.
The correct answer is (C).
Solution
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Question No. 8 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
8. Which organic compound is acidic?
Question
(A) C2H6
(B) CH3Cl
(C) HCOOH
(D) CH3OH
(E) C6H12O6
A. Incorrect!
Hydrocarbons do not dissociate.
B. Incorrect!
Halo-hydrocarbons do not dissociate.
C. Correct!
Carboxylic acids dissociate slightly to provide acidic hydrogen to the solution.
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D. Incorrect!
Alcohols do not dissociate.
E. Incorrect!
Sugar will not dissociate.
Carboxylic acids are weak acids, therefore they dissociate slightly to provide acidic
hydrogen to the solution.
The correct answer is (C).
Solution
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Question No. 9 of 10
Instructions: (1) Read the problem statement and answer choices carefully (2) Work the problems
on paper as needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
9. Which of the following is not an organic functional group?
Question
(A) alcohol
(B) carbonyl
(C) amine
(D) ammonium
(E) none of the above
A. Incorrect!
Alcohol is an organic functional group.
B. Incorrect!
A carbonyl is an organic functional group.
C. Incorrect!
An amine is an organic functional group.
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D. Correct!
Ammonium is a cation, not an organic functional group.
E. Incorrect!
There is a choice listed that is not an organic functional group.
Ammonium is a cation, not an organic functional group. The rest of the choices
(alcohol, carbonyl and amine) are organic functional groups.
The correct answer is (D).
Solution
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Question No. 10 of 10
Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as
needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed.
10. Which of the following is a structural isomer for CH2=CH-CH2-CH3?
Question
(A) CH3-CH(CH3)-CH3
(B) CH3-CH=CH-CH3
(C) CH3-CH2-CH=CH2
(D) All of the above
(E) None of the above
A. Incorrect!
This molecule has more hydrogen atoms than the original molecule.
B. Correct!
This molecule has the double bond between the second and third carbon atoms
rather than the first and second as the original molecule.
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C. Incorrect!
Both this molecule and the original molecule have the double bond between the
first and second carbon (remember you always count from the carbon closest to the
double bond).
D. Incorrect!
Only one of them is a structural isomer.
E. Incorrect!
One of them is a structural isomer.
Structural isomers are two molecules with the same chemical formula, but a
different bonding structure.
Option A had too many hydrogen atoms and Option C was the same as the original
molecule, only flipped horizontally.
The correct answer is (B).
Solution
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