Q. If 5 g of CaCO3 decomposes completely, how many grams of CaO are produced?
-
A.
2 g
-
B.
3 g
-
C.
4 g
-
D.
5 g
Solution
CaCO3 → CaO + CO2. Molar mass of CaCO3 = 100 g, CaO = 56 g. 5 g of CaCO3 produces (5 g * 56 g) / 100 g = 2.8 g of CaO.
Correct Answer: C — 4 g
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Q. If 5 liters of a 20% solution is mixed with 15 liters of a 30% solution, what is the percentage concentration of the resulting mixture?
-
A.
24%
-
B.
26%
-
C.
28%
-
D.
30%
Solution
Total salt = (0.2*5) + (0.3*15) = 1 + 4.5 = 5.5 liters. Total volume = 5 + 15 = 20 liters. Concentration = (5.5/20)*100 = 27.5%.
Correct Answer: A — 24%
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Q. If 5 moles of KCl are dissolved in 1 kg of water, what is the molality of the solution?
-
A.
5 m
-
B.
2.5 m
-
C.
10 m
-
D.
1 m
Solution
Molality (m) = moles of solute / kg of solvent = 5 moles / 1 kg = 5 m.
Correct Answer: A — 5 m
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Q. If 5 moles of KCl are dissolved in 3 kg of water, what is the molality of the solution?
-
A.
1.67 m
-
B.
2.5 m
-
C.
1.25 m
-
D.
0.5 m
Solution
Molality (m) = moles of solute / kg of solvent = 5 moles / 3 kg = 1.67 m.
Correct Answer: A — 1.67 m
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Q. If 5 moles of NaCl are dissolved in water, how many moles of Na+ ions are present?
-
A.
5 moles
-
B.
10 moles
-
C.
2.5 moles
-
D.
0 moles
Solution
Each mole of NaCl dissociates into 1 mole of Na+ ions. Therefore, 5 moles of NaCl will produce 5 moles of Na+ ions.
Correct Answer: A — 5 moles
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Q. If 5 workers can complete a task in 10 days, how many days will 10 workers take to complete the same task? (2023)
-
A.
5 days
-
B.
10 days
-
C.
15 days
-
D.
20 days
Solution
If 5 workers take 10 days, 10 workers will take 10/2 = 5 days.
Correct Answer: A — 5 days
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Q. If 50 g of KCl is dissolved in 250 mL of solution, what is the molarity? (Molar mass of KCl = 74.5 g/mol)
-
A.
2.68 M
-
B.
1.34 M
-
C.
0.67 M
-
D.
0.25 M
Solution
Moles of KCl = 50 g / 74.5 g/mol = 0.672 moles. Molarity = 0.672 moles / 0.25 L = 2.688 M.
Correct Answer: B — 1.34 M
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Q. If 50 grams of a solute is dissolved in 200 mL of solution, what is the mass/volume percent concentration?
-
A.
25%
-
B.
20%
-
C.
15%
-
D.
10%
Solution
Mass/volume percent = (mass of solute / volume of solution) * 100 = (50 g / 200 mL) * 100 = 25%.
Correct Answer: A — 25%
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Q. If 50 grams of NaCl is dissolved in 1 liter of solution, what is the molarity? (Molar mass of NaCl = 58.5 g/mol)
-
A.
0.85 M
-
B.
1.0 M
-
C.
1.5 M
-
D.
2.0 M
Solution
Moles of NaCl = 50 g / 58.5 g/mol = 0.854 moles. Molarity = 0.854 moles / 1 L = 0.854 M.
Correct Answer: B — 1.0 M
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Q. If 50 grams of NaOH is dissolved in 1 liter of solution, what is the molarity? (Molar mass of NaOH = 40 g/mol)
-
A.
1.25 M
-
B.
2.5 M
-
C.
0.5 M
-
D.
1 M
Solution
Moles of NaOH = 50 g / 40 g/mol = 1.25 moles. Molarity = 1.25 moles / 1 L = 1.25 M.
Correct Answer: B — 2.5 M
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Q. If 50 mL of 0.1 M H2SO4 is diluted to 250 mL, what is the new concentration?
-
A.
0.02 M
-
B.
0.04 M
-
C.
0.1 M
-
D.
0.5 M
Solution
C1V1 = C2V2; (0.1 M)(50 mL) = C2(250 mL); C2 = 0.02 M.
Correct Answer: B — 0.04 M
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Q. If 50 mL of 0.1 M HCl is mixed with 50 mL of 0.1 M NaOH, what is the resulting pH?
Solution
HCl and NaOH neutralize each other, resulting in a neutral solution with pH = 7.
Correct Answer: A — 7
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Q. If 50 mL of a 2 M HCl solution is diluted to 200 mL, what is the new molarity?
-
A.
0.25 M
-
B.
0.5 M
-
C.
1 M
-
D.
2 M
Solution
Using the dilution formula M1V1 = M2V2, (2 M)(50 mL) = M2(200 mL) => M2 = 0.5 M.
Correct Answer: B — 0.5 M
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Q. If 50 mL of a 3 M solution is diluted to 200 mL, what is the new molarity? (2020)
-
A.
0.75 M
-
B.
1.5 M
-
C.
2 M
-
D.
3 M
Solution
Using M1V1 = M2V2, (3 M)(50 mL) = M2(200 mL) => M2 = (3 M × 50 mL) / 200 mL = 0.75 M.
Correct Answer: A — 0.75 M
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Q. If 50% of students like soccer, 30% like basketball, and 10% like both, what percentage of students like only soccer?
-
A.
40%
-
B.
30%
-
C.
20%
-
D.
10%
Solution
The percentage of students who like only soccer is 50% - 10% = 40%.
Correct Answer: A — 40%
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Q. If 500 J of heat is added to a system and 200 J of work is done by the system, what is the change in internal energy?
-
A.
300 J
-
B.
500 J
-
C.
700 J
-
D.
200 J
Solution
According to the first law of thermodynamics, ΔU = Q - W. Here, ΔU = 500 J - 200 J = 300 J.
Correct Answer: A — 300 J
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Q. If 500 J of heat is added to a system and 200 J of work is done by the system, what is the change in internal energy of the system?
-
A.
300 J
-
B.
500 J
-
C.
700 J
-
D.
200 J
Solution
According to the first law of thermodynamics, ΔU = Q - W. Here, ΔU = 500 J - 200 J = 300 J.
Correct Answer: A — 300 J
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Q. If 500 J of heat is added to a system and it does 200 J of work, what is the change in internal energy? (2022)
-
A.
300 J
-
B.
200 J
-
C.
500 J
-
D.
700 J
Solution
According to the first law of thermodynamics, ΔU = Q - W. Here, ΔU = 500 J - 200 J = 300 J.
Correct Answer: A — 300 J
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Q. If 5m + 15 = 45, what is the value of m? (2023)
Solution
5m + 15 = 45 => 5m = 30 => m = 6.
Correct Answer: A — 5
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Q. If 5x - 7 < 3, what is the range of x?
-
A.
x < 2
-
B.
x > 2
-
C.
x < 1
-
D.
x > 1
Solution
5x - 7 < 3 => 5x < 10 => x < 2
Correct Answer: A — x < 2
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Q. If 5x - 7 < 3, what is the value of x?
-
A.
x < 2
-
B.
x > 2
-
C.
x < 1
-
D.
x > 1
Solution
5x - 7 < 3 => 5x < 10 => x < 2
Correct Answer: A — x < 2
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Q. If 5x - 7 < 3x + 1, what is the range of x?
-
A.
x < 4
-
B.
x > 4
-
C.
x < 2
-
D.
x > 2
Solution
5x - 7 < 3x + 1 => 2x < 8 => x < 4.
Correct Answer: A — x < 4
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Q. If 5x = 25, what is the value of x? (2019)
Solution
5x = 25, so x = 25/5 = 5.
Correct Answer: A — 5
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Q. If 5^(x+1) = 125, what is the value of x?
Solution
125 = 5^3, so x + 1 = 3, hence x = 2.
Correct Answer: B — 2
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Q. If 5^(x-1) = 25, what is the value of x?
Solution
Since 25 = 5^2, we have 5^(x-1) = 5^2, thus x - 1 = 2, giving x = 3.
Correct Answer: A — 2
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Q. If 5^x = 125, what is the value of x?
Solution
125 = 5^3 => x = 3
Correct Answer: C — 3
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Q. If 5^x = 25, what is the value of x?
Solution
Since 25 = 5^2, we have 5^x = 5^2, thus x = 2.
Correct Answer: B — 2
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Q. If 6 different colored balls are to be arranged in a row, how many arrangements are possible?
-
A.
720
-
B.
600
-
C.
360
-
D.
480
Solution
The number of arrangements of 6 different colored balls is 6! = 720.
Correct Answer: A — 720
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Q. If 60% of students like reading fiction, 40% like reading non-fiction, and 10% like both, what percentage of students like only fiction?
-
A.
50%
-
B.
40%
-
C.
30%
-
D.
20%
Solution
The percentage of students who like only fiction is 60% - 10% = 50%.
Correct Answer: A — 50%
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Q. If 60% of students like reading, 40% like writing, and 10% like both, what percentage of students like either reading or writing?
-
A.
90%
-
B.
80%
-
C.
70%
-
D.
60%
Solution
Using inclusion-exclusion, the percentage is 60% + 40% - 10% = 90%.
Correct Answer: A — 90%
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