Q. How many ways can a committee of 4 be formed from 8 people? (2019)
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Solution
The number of ways to form a committee of 4 from 8 is 8C4 = 70.
Correct Answer: A — 70
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Q. How much heat is required to raise the temperature of 250 g of water from 25°C to 75°C? (Specific heat of water = 4.2 J/g°C) (2020)
A.
5250 J
B.
4200 J
C.
2500 J
D.
1000 J
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Solution
Heat required = mass × specific heat × change in temperature = 250 g × 4.2 J/g°C × (75°C - 25°C) = 5250 J.
Correct Answer: A — 5250 J
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Q. How much heat is required to raise the temperature of 500 g of water from 25°C to 75°C? (2020)
A.
10000 J
B.
5000 J
C.
20000 J
D.
15000 J
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Solution
Q = mcΔT = 500 g * 4.2 J/g°C * (75 - 25)°C = 10000 J.
Correct Answer: D — 15000 J
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Q. How much work is done when a force of 10 N moves an object 5 m in the direction of the force?
A.
25 J
B.
50 J
C.
75 J
D.
100 J
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Solution
Work = Force * Distance = 10 N * 5 m = 50 J.
Correct Answer: B — 50 J
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Q. How much work is done when a force of 15 N moves an object 3 m in the direction of the force?
A.
45 J
B.
30 J
C.
15 J
D.
60 J
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Solution
Work done = Force × Distance = 15 N × 3 m = 45 J
Correct Answer: A — 45 J
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Q. How much work is done when a force of 30 N moves an object 4 m in the direction of the force?
A.
120 J
B.
90 J
C.
60 J
D.
30 J
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Solution
Work = Force * Distance = 30 N * 4 m = 120 J.
Correct Answer: A — 120 J
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Q. Identify the oxidizing agent in the reaction: 2H2 + O2 → 2H2O. (2023)
A.
H2
B.
O2
C.
H2O
D.
None of the above
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Solution
O2 is the oxidizing agent as it gains electrons and is reduced to H2O.
Correct Answer: B — O2
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Q. If 0.1 M acetic acid (CH3COOH) is 1% ionized, what is the concentration of H+ ions?
A.
0.001 M
B.
0.01 M
C.
0.1 M
D.
0.2 M
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Solution
Ionization = 1% of 0.1 M = 0.001 M, so [H+] = 0.001 M.
Correct Answer: B — 0.01 M
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Q. If 0.1 M acetic acid has a pH of 2.87, what is the concentration of H+ ions?
A.
0.001 M
B.
0.01 M
C.
0.1 M
D.
0.5 M
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Solution
[H+] = 10^(-pH) = 10^(-2.87) ≈ 0.001 M.
Correct Answer: B — 0.01 M
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Q. If 0.5 moles of a gas occupy 12 liters at STP, what is the molar volume of the gas? (2023)
A.
22.4 L
B.
24 L
C.
12 L
D.
6 L
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Solution
At STP, 1 mole of any gas occupies 22.4 L. Therefore, 0.5 moles occupy 0.5 x 22.4 L = 11.2 L, confirming the molar volume is 22.4 L.
Correct Answer: A — 22.4 L
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Q. If 0.5 moles of a gas occupy 12.2 liters at STP, what is the molar volume of the gas? (2023)
A.
22.4 L
B.
24 L
C.
12.2 L
D.
6.1 L
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Solution
At STP, 1 mole of gas occupies 22.4 liters. Therefore, the molar volume is 22.4 L.
Correct Answer: A — 22.4 L
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Q. If 1 kg of water is heated from 25°C to 75°C, how much heat is absorbed? (Specific heat of water = 4.2 J/g°C) (2021)
A.
21000 J
B.
42000 J
C.
84000 J
D.
105000 J
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Solution
Q = mcΔT = (1000 g)(4.2 J/g°C)(50°C) = 210000 J.
Correct Answer: B — 42000 J
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Q. If 1 mole of a gas occupies 22.4 liters at STP, how many liters will 0.5 moles occupy? (2023)
A.
11.2 L
B.
22.4 L
C.
44.8 L
D.
5.6 L
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Solution
At STP, 1 mole of gas occupies 22.4 L. Therefore, 0.5 moles will occupy 0.5 x 22.4 L = 11.2 L.
Correct Answer: A — 11.2 L
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Q. If 10 g of glucose (C6H12O6) is dissolved in 200 g of water, what is the mass percentage of the solution? (2023)
A.
4.76%
B.
5.00%
C.
10.00%
D.
2.50%
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Solution
Mass percentage = (mass of solute / mass of solution) x 100. Mass of solution = 10 g + 200 g = 210 g. Mass percentage = (10 g / 210 g) x 100 = 4.76%.
Correct Answer: A — 4.76%
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Q. If 10 g of sugar (C12H22O11) is dissolved in 200 g of water, what is the mass percent of the sugar solution? (2023)
A.
4.76%
B.
5.00%
C.
10.00%
D.
2.50%
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Solution
Mass percent = (mass of solute / mass of solution) x 100. Mass of solution = 10 g + 200 g = 210 g. Mass percent = (10 g / 210 g) x 100 = 4.76%.
Correct Answer: A — 4.76%
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Q. If 10 g of sugar (C12H22O11) is dissolved in 200 g of water, what is the mass percent of sugar in the solution? (Molar mass of sugar = 342 g/mol) (2023)
A.
4.76%
B.
5.00%
C.
10.00%
D.
2.50%
Show solution
Solution
Mass percent = (mass of solute / total mass of solution) x 100. Total mass = 10 g + 200 g = 210 g. Mass percent = (10 g / 210 g) x 100 = 4.76%.
Correct Answer: A — 4.76%
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Q. If 10 g of sugar (C12H22O11) is dissolved in 200 g of water, what is the mass percent of the solution? (Molar mass of sugar = 342 g/mol) (2023)
A.
4.76%
B.
5.00%
C.
10.00%
D.
2.50%
Show solution
Solution
Mass percent = (mass of solute / mass of solution) x 100. Mass of solution = 10 g + 200 g = 210 g. Mass percent = (10 g / 210 g) x 100 = 4.76%.
Correct Answer: B — 5.00%
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Q. If 10 g of sugar (C12H22O11) is dissolved in 200 g of water, what is the mass percent of the solution? (2023)
A.
4.76%
B.
5.00%
C.
10.00%
D.
20.00%
Show solution
Solution
Mass percent = (mass of solute / mass of solution) × 100. Mass of solution = 10 g + 200 g = 210 g. Mass percent = (10 g / 210 g) × 100 = 4.76%.
Correct Answer: B — 5.00%
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Q. If 10 g of sugar (C12H22O11) is dissolved in 200 g of water, what is the mass percentage of the solution? (Molar mass of sugar = 342 g/mol) (2023)
A.
4.76%
B.
5.00%
C.
10.00%
D.
2.50%
Show solution
Solution
Mass percentage = (mass of solute / mass of solution) x 100. Mass of solution = 10 g + 200 g = 210 g. Mass percentage = (10 g / 210 g) x 100 = 4.76%.
Correct Answer: B — 5.00%
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Q. If 10 g of sugar (C12H22O11) is dissolved in 200 g of water, what is the mass percentage of the sugar solution? (Molar mass of sugar = 342 g/mol) (2023)
A.
4.76%
B.
5.00%
C.
10.00%
D.
2.50%
Show solution
Solution
Mass percentage = (mass of solute / mass of solution) x 100. Mass of solution = 10 g + 200 g = 210 g. Mass percentage = (10 g / 210 g) x 100 = 4.76%.
Correct Answer: A — 4.76%
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Q. If 10 g of sugar is dissolved in 100 g of water, what is the mass percent of sugar in the solution? (2023)
A.
10%
B.
5%
C.
20%
D.
15%
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Solution
Mass percent = (mass of solute / total mass of solution) x 100. Total mass = 10 g + 100 g = 110 g. Mass percent = (10 g / 110 g) x 100 = 9.09%, approximately 10%.
Correct Answer: A — 10%
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Q. If 10 g of sugar is dissolved in 100 g of water, what is the mass percentage of sugar in the solution? (2023)
A.
10%
B.
5%
C.
20%
D.
15%
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Solution
Mass percentage = (mass of solute / mass of solution) × 100. Mass of solution = 10 g + 100 g = 110 g. Mass percentage = (10 g / 110 g) × 100 = 9.09%, approximately 10%.
Correct Answer: A — 10%
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Q. If 10 grams of NaCl is dissolved in 500 mL of water, what is the concentration in g/L? (2020)
A.
20 g/L
B.
10 g/L
C.
5 g/L
D.
15 g/L
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Solution
Concentration = (10 g / 0.5 L) = 20 g/L.
Correct Answer: A — 20 g/L
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Q. If 10 grams of NaCl is dissolved in 500 mL of water, what is the mass/volume percent concentration? (2020) 2020
A.
2%
B.
5%
C.
10%
D.
20%
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Solution
Mass/volume % = (mass of solute / volume of solution) * 100 = (10 g / 500 mL) * 100 = 2%.
Correct Answer: B — 5%
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Q. If 1000 J of heat is added to a gas and it expands doing 400 J of work, what is the change in internal energy? (2023)
A.
600 J
B.
400 J
C.
1000 J
D.
200 J
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Solution
Using the first law of thermodynamics: ΔU = Q - W = 1000 J - 400 J = 600 J.
Correct Answer: A — 600 J
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Q. If 1000 J of heat is added to a system and it does 400 J of work, what is the change in internal energy? (2021)
A.
600 J
B.
400 J
C.
1000 J
D.
1400 J
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Solution
Using the first law of thermodynamics, ΔU = Q - W = 1000 J - 400 J = 600 J.
Correct Answer: A — 600 J
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Q. If 15 g of sugar is dissolved in 300 mL of water, what is the concentration in g/mL? (2020)
A.
0.05 g/mL
B.
0.1 g/mL
C.
0.15 g/mL
D.
0.2 g/mL
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Solution
Concentration = mass / volume = 15 g / 300 mL = 0.05 g/mL.
Correct Answer: B — 0.1 g/mL
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Q. If 20 grams of glucose (C6H12O6) is dissolved in 1 liter of water, what is the molarity of the solution? (Molar mass of glucose = 180 g/mol) (2020) 2020
A.
0.11 M
B.
0.5 M
C.
0.2 M
D.
0.33 M
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Solution
Moles of glucose = 20 g / 180 g/mol = 0.111 M. Molarity = 0.111 moles / 1 L = 0.11 M.
Correct Answer: A — 0.11 M
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Q. If 200 g of water at 80°C is mixed with 300 g of water at 20°C, what will be the final temperature of the mixture? (Assume no heat loss to the surroundings)
A.
30°C
B.
40°C
C.
50°C
D.
60°C
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Solution
Using the formula m1c1T1 + m2c2T2 = (m1 + m2)cTfinal, we find Tfinal = 40°C.
Correct Answer: B — 40°C
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Q. If 200 J of heat is added to a system and 50 J of work is done by the system, what is the change in internal energy of the system?
A.
150 J
B.
250 J
C.
200 J
D.
100 J
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Solution
According to the first law of thermodynamics, ΔU = Q - W = 200 J - 50 J = 150 J.
Correct Answer: A — 150 J
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