Q. How many different ways can the letters of the word 'BOOK' be arranged? (2014)
Solution
The number of arrangements of the letters in 'BOOK' is 4! / 2! = 12.
Correct Answer: B — 24
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Q. How many different ways can the letters of the word 'MATH' be arranged?
Solution
The number of arrangements of the letters in 'MATH' is 4! = 24.
Correct Answer: B — 24
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Q. How many grams are in 0.5 moles of glucose (C6H12O6)? (2023)
-
A.
90 g
-
B.
180 g
-
C.
45 g
-
D.
60 g
Solution
Molar mass of C6H12O6 = 6*12 + 12*1 + 6*16 = 180 g/mol. Mass = 0.5 moles x 180 g/mol = 90 g.
Correct Answer: A — 90 g
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Q. How many grams are in 4 moles of potassium chloride (KCl)? (2022)
-
A.
74 g
-
B.
148 g
-
C.
296 g
-
D.
37 g
Solution
Molar mass of KCl = 39 + 35.5 = 74.5 g/mol. Mass = 4 moles x 74.5 g/mol = 298 g.
Correct Answer: C — 296 g
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Q. How many grams are in 4 moles of sulfuric acid (H2SO4)? (2023)
-
A.
196 g
-
B.
98 g
-
C.
392 g
-
D.
294 g
Solution
Molar mass of H2SO4 = 2*1 + 32 + 4*16 = 98 g/mol. Mass = 4 moles x 98 g/mol = 392 g.
Correct Answer: C — 392 g
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Q. How many grams of KCl are needed to prepare 0.5 M solution in 500 mL of water? (2023)
-
A.
14.9 g
-
B.
7.45 g
-
C.
29.8 g
-
D.
3.73 g
Solution
Molarity = moles/volume(L). Moles = 0.5 mol/L * 0.5 L = 0.25 mol. Mass = moles * molar mass = 0.25 mol * 74.5 g/mol = 18.625 g.
Correct Answer: B — 7.45 g
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Q. How many grams of KCl are needed to prepare 250 mL of a 0.5 M solution? (2023) 2023
-
A.
7.45 g
-
B.
12.5 g
-
C.
9.25 g
-
D.
5.25 g
Solution
Molar mass of KCl = 74.55 g/mol. Grams = Molarity * Volume (L) * Molar mass = 0.5 M * 0.25 L * 74.55 g/mol = 9.31 g.
Correct Answer: A — 7.45 g
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Q. How many grams of KCl are needed to prepare 250 mL of a 2 M solution? (2023)
-
A.
37.25 g
-
B.
50 g
-
C.
75 g
-
D.
25 g
Solution
Molar mass of KCl = 74.55 g/mol. Grams = moles × molar mass = 0.5 moles × 74.55 g/mol = 37.25 g.
Correct Answer: A — 37.25 g
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Q. How many grams of KCl are needed to prepare 250 mL of a 2 M solution? (Molar mass of KCl = 74.5 g/mol) (2023)
-
A.
37.25 g
-
B.
74.5 g
-
C.
18.625 g
-
D.
9.25 g
Solution
Grams = moles × molar mass = (2 moles/L × 0.25 L) × 74.5 g/mol = 37.25 g.
Correct Answer: A — 37.25 g
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Q. How many liters of a 0.5 M NaOH solution are needed to obtain 1 mole of NaOH? (2023)
-
A.
1 L
-
B.
2 L
-
C.
0.5 L
-
D.
0.25 L
Solution
Volume = moles / molarity = 1 mole / 0.5 M = 2 L.
Correct Answer: A — 1 L
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Q. How many liters of a 0.5 M solution contain 2 moles of solute? (2023)
-
A.
2 L
-
B.
4 L
-
C.
1 L
-
D.
0.5 L
Solution
Volume = moles / molarity = 2 moles / 0.5 M = 4 L
Correct Answer: B — 4 L
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Q. How many liters of a 3 M solution can be made from 6 moles of solute? (2023)
-
A.
1 L
-
B.
2 L
-
C.
3 L
-
D.
4 L
Solution
Volume = moles / molarity = 6 moles / 3 M = 2 L.
Correct Answer: B — 2 L
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Q. How many molecules are in 0.1 moles of oxygen gas (O2)? (2021)
-
A.
6.022 x 10^22
-
B.
6.022 x 10^23
-
C.
1.2044 x 10^23
-
D.
3.011 x 10^23
Solution
Number of molecules = moles x Avogadro's number = 0.1 moles x 6.022 x 10^23 molecules/mole = 6.022 x 10^22 molecules.
Correct Answer: A — 6.022 x 10^22
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Q. How many molecules are in 0.25 moles of oxygen gas (O2)? (2022)
-
A.
3.011 x 10^23
-
B.
6.022 x 10^22
-
C.
1.2044 x 10^23
-
D.
1.5055 x 10^23
Solution
Number of molecules = moles x Avogadro's number = 0.25 moles x 6.022 x 10^23 molecules/mole = 1.5055 x 10^23 molecules.
Correct Answer: B — 6.022 x 10^22
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Q. How many molecules are present in 2 moles of water (H2O)? (2022) 2022
-
A.
6.022 x 10^23
-
B.
1.2044 x 10^24
-
C.
3.011 x 10^23
-
D.
1.2044 x 10^23
Solution
Number of molecules = moles x Avogadro's number = 2 moles x 6.022 x 10^23 molecules/mole = 1.2044 x 10^24 molecules.
Correct Answer: B — 1.2044 x 10^24
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Q. How many moles are in 100 grams of NaOH? (2022)
-
A.
2.5
-
B.
1.25
-
C.
0.5
-
D.
3
Solution
Molar mass of NaOH = 23 + 16 + 1 = 40 g/mol. Number of moles = mass/molar mass = 100 g / 40 g/mol = 2.5 moles.
Correct Answer: B — 1.25
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Q. How many moles are in 32 grams of O2? (2021)
Solution
Molar mass of O2 = 16*2 = 32 g/mol. Number of moles = mass/molar mass = 32g/32g/mol = 1 mole.
Correct Answer: A — 1
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Q. How many moles of solute are present in 500 mL of a 0.2 M solution? (2021) 2021
-
A.
0.1 moles
-
B.
0.5 moles
-
C.
0.2 moles
-
D.
0.25 moles
Solution
Moles = Molarity * Volume (L) = 0.2 M * 0.5 L = 0.1 moles.
Correct Answer: A — 0.1 moles
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Q. How many orbitals are present in the d-subshell? (2023)
Solution
The d-subshell has 5 orbitals.
Correct Answer: C — 5
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Q. How many orbitals are present in the p subshell? (2023)
Solution
The p subshell has 3 orbitals (px, py, pz).
Correct Answer: C — 3
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Q. How many ways can 2 boys and 2 girls be selected from 5 boys and 5 girls? (2020)
-
A.
100
-
B.
150
-
C.
200
-
D.
300
Solution
The number of ways to select 2 boys from 5 is C(5, 2) and 2 girls from 5 is C(5, 2). Total = C(5, 2) * C(5, 2) = 10 * 10 = 100.
Correct Answer: B — 150
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Q. How many ways can 2 boys and 3 girls be selected from 5 boys and 6 girls?
-
A.
100
-
B.
150
-
C.
200
-
D.
250
Solution
The number of ways is 5C2 * 6C3 = 10 * 20 = 200.
Correct Answer: B — 150
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Q. How many ways can 2 boys and 3 girls be selected from 5 boys and 7 girls? (2020)
-
A.
210
-
B.
300
-
C.
350
-
D.
400
Solution
The number of ways is 5C2 * 7C3 = 10 * 35 = 350.
Correct Answer: C — 350
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Q. How many ways can 2 boys and 3 girls be selected from 8 boys and 6 girls?
-
A.
336
-
B.
280
-
C.
420
-
D.
180
Solution
The number of ways is 8C2 * 6C3 = 28 * 20 = 560.
Correct Answer: A — 336
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Q. How many ways can 2 boys and 3 girls be selected from a group of 5 boys and 7 girls? (2018)
-
A.
210
-
B.
300
-
C.
150
-
D.
100
Solution
The number of ways to select 2 boys from 5 is 5C2 and 3 girls from 7 is 7C3. Total = 5C2 * 7C3 = 10 * 35 = 350.
Correct Answer: A — 210
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Q. How many ways can 2 students be selected from a group of 5? (2019)
Solution
The number of ways to select 2 students from 5 is given by 5C2 = 10.
Correct Answer: A — 10
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Q. How many ways can 2 students be selected from a group of 8? (2015)
Solution
The number of ways to select 2 from 8 is C(8, 2) = 28.
Correct Answer: A — 28
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Q. How many ways can 3 books be selected from a shelf of 10 books? (2022)
-
A.
120
-
B.
210
-
C.
100
-
D.
30
Solution
The number of ways to select 3 books from 10 is given by 10C3 = 120.
Correct Answer: B — 210
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Q. How many ways can 3 boys and 2 girls be seated in a row?
-
A.
30
-
B.
60
-
C.
120
-
D.
180
Solution
The number of ways to arrange 5 people is 5! = 120.
Correct Answer: C — 120
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Q. How many ways can 3 different books be chosen from a set of 7?
Solution
The number of ways to choose 3 from 7 is C(7, 3) = 35.
Correct Answer: A — 35
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