Engineering Entrance
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 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 12.2 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 sugar in the solution? (Molar mass of sugar = 342 g/mol) (2023)
A.
4.76%
B.
5.00%
C.
10.00%
D.
2.50%
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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 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 2x = 10, what is the value of x? (2015)
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Solution
Dividing both sides by 2 gives x = 10/2 = 5.
Correct Answer: A — 5
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Q. If 3 moles of glucose are dissolved in 1 liter of solution, what is the molality of the solution? (2023)
A.
3 m
B.
1 m
C.
2 m
D.
0.5 m
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Solution
Molality (m) = moles of solute / kg of solvent; assuming 1 L of water = 1 kg, m = 3 moles / 1 kg = 3 m
Correct Answer: A — 3 m
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Q. If 3x = 12, what is the value of x? (2019)
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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
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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 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
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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 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
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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
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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 5x = 25, what is the value of x? (2019)
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Solution
5x = 25, so x = 25/5 = 5.
Correct Answer: A — 5
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Q. If a 10 kg object is raised to a height of 5 m, what is the work done against gravity? (g = 9.8 m/s²)
A.
490 J
B.
980 J
C.
150 J
D.
250 J
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Solution
Work = m * g * h = 10 kg * 9.8 m/s² * 5 m = 490 J.
Correct Answer: B — 980 J
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Q. If a 10 N force is applied at an angle of 60 degrees to the horizontal while moving an object 3 m, what is the work done? (2020)
A.
15 J
B.
30 J
C.
25 J
D.
5 J
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Solution
Work done = Force × Distance × cos(θ) = 10 N × 3 m × cos(60°) = 10 N × 3 m × 0.5 = 15 J
Correct Answer: A — 15 J
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Q. If a 1000 kg car is moving with a speed of 15 m/s, what is its kinetic energy?
A.
112,500 J
B.
225,000 J
C.
75,000 J
D.
150,000 J
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Solution
Kinetic Energy = 0.5 × mass × velocity² = 0.5 × 1000 kg × (15 m/s)² = 112,500 J
Correct Answer: B — 225,000 J
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