Q. Which of the following reactions has a negative enthalpy change?
-
A.
Dissolving NaCl in water
-
B.
Photosynthesis
-
C.
Respiration
-
D.
Melting of ice
Solution
Respiration is an exothermic reaction that releases energy, resulting in a negative enthalpy change.
Correct Answer: C — Respiration
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Q. Which of the following reactions has a positive ΔG at standard conditions?
-
A.
Combustion of glucose
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B.
Formation of water from hydrogen and oxygen
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C.
Dissolution of salt in water
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D.
Decomposition of hydrogen peroxide
Solution
The decomposition of hydrogen peroxide is non-spontaneous under standard conditions, resulting in a positive ΔG.
Correct Answer: D — Decomposition of hydrogen peroxide
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Q. Which of the following reactions has a positive ΔH and a positive ΔS?
-
A.
Combustion of fuels
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B.
Dissolution of salts
-
C.
Sublimation of dry ice
-
D.
Formation of water from hydrogen and oxygen
Solution
Sublimation of dry ice (solid CO2 to gas) has a positive ΔH (endothermic) and a positive ΔS (increase in disorder).
Correct Answer: C — Sublimation of dry ice
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Q. Which of the following reactions has the highest enthalpy change?
-
A.
Dissolving NaCl in water
-
B.
Combustion of propane
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C.
Formation of NH3 from N2 and H2
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D.
Sublimation of dry ice
Solution
The combustion of propane releases a large amount of energy, resulting in the highest enthalpy change among the options.
Correct Answer: B — Combustion of propane
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Q. Which of the following reactions is a redox reaction?
-
A.
H2 + Cl2 → 2HCl
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B.
NaOH + HCl → NaCl + H2O
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C.
CaCO3 → CaO + CO2
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D.
C6H12O6 + 6O2 → 6CO2 + 6H2O
Solution
The combustion of glucose is a redox reaction where glucose is oxidized.
Correct Answer: D — C6H12O6 + 6O2 → 6CO2 + 6H2O
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Q. Which of the following reactions is expected to have a positive change in entropy?
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A.
N2(g) + 3H2(g) → 2NH3(g)
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B.
C(s) + O2(g) → CO2(g)
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C.
2H2O(l) → 2H2(g) + O2(g)
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D.
CaCO3(s) → CaO(s) + CO2(g)
Solution
The decomposition of liquid water into gaseous hydrogen and oxygen increases the number of gas molecules, leading to a positive change in entropy.
Correct Answer: C — 2H2O(l) → 2H2(g) + O2(g)
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Q. Which of the following reactions is likely to have a negative ΔG?
-
A.
Combustion of hydrocarbons.
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B.
Formation of ice from water at 0°C.
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C.
Dissolution of salt in water.
-
D.
Decomposition of hydrogen peroxide.
Solution
The combustion of hydrocarbons is highly exothermic and typically has a negative ΔG, indicating spontaneity.
Correct Answer: A — Combustion of hydrocarbons.
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Q. Which of the following reactions is spontaneous at all temperatures?
-
A.
ΔH < 0 and ΔS < 0
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B.
ΔH > 0 and ΔS > 0
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C.
ΔH < 0 and ΔS > 0
-
D.
ΔH > 0 and ΔS < 0
Solution
A reaction with ΔH < 0 and ΔS > 0 is spontaneous at all temperatures because it results in a negative ΔG.
Correct Answer: C — ΔH < 0 and ΔS > 0
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Q. Which of the following reactions will have a negative ΔG at high temperatures?
-
A.
Exothermic reactions with negative ΔS
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B.
Endothermic reactions with positive ΔS
-
C.
Exothermic reactions with positive ΔS
-
D.
Endothermic reactions with negative ΔS
Solution
Endothermic reactions with positive ΔS can have a negative ΔG at high temperatures due to the TΔS term becoming significant.
Correct Answer: B — Endothermic reactions with positive ΔS
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Q. Which of the following represents a physical change?
-
A.
Burning wood
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B.
Dissolving sugar in water
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C.
Rusting of iron
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D.
Cooking an egg
Solution
Dissolving sugar in water is a physical change as it does not alter the chemical composition of sugar.
Correct Answer: B — Dissolving sugar in water
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Q. Which of the following represents an endothermic reaction?
-
A.
Combustion of gasoline
-
B.
Dissolving ammonium nitrate in water
-
C.
Respiration
-
D.
Rusting of iron
Solution
Dissolving ammonium nitrate in water absorbs heat, making it an endothermic reaction.
Correct Answer: B — Dissolving ammonium nitrate in water
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Q. Which of the following represents the correct relationship between moles and mass?
-
A.
Moles = Mass / Molar Mass
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B.
Mass = Moles x Molar Mass
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C.
Molar Mass = Mass / Moles
-
D.
All of the above
Solution
All the given relationships are correct and represent the conversion between moles, mass, and molar mass.
Correct Answer: D — All of the above
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Q. Which of the following represents the correct relationship between moles, mass, and molar mass?
-
A.
moles = mass × molar mass
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B.
mass = moles × molar mass
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C.
molar mass = mass / moles
-
D.
mass = moles / molar mass
Solution
The correct relationship is mass = moles × molar mass.
Correct Answer: B — mass = moles × molar mass
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Q. Which of the following represents the enthalpy change for a reaction at constant pressure?
Solution
The enthalpy change for a reaction at constant pressure is represented by ΔH.
Correct Answer: B — ΔH
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Q. Which of the following represents the number of particles in one mole of a substance?
-
A.
6.022 x 10^23
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B.
3.14 x 10^22
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C.
1.6 x 10^19
-
D.
9.11 x 10^28
Solution
Avogadro's number is 6.022 x 10^23, which represents the number of particles in one mole.
Correct Answer: A — 6.022 x 10^23
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Q. Which of the following salts will produce a basic solution when dissolved in water?
-
A.
NaCl
-
B.
KNO3
-
C.
NH4Cl
-
D.
Na2CO3
Solution
Na2CO3 is a salt of a weak acid (H2CO3) and a strong base (NaOH), thus it will produce a basic solution.
Correct Answer: D — Na2CO3
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Q. Which of the following sets of quantum numbers corresponds to a 3p electron?
-
A.
n=3, l=0, m_l=0
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B.
n=3, l=1, m_l=1
-
C.
n=2, l=1, m_l=0
-
D.
n=3, l=2, m_l=0
Solution
For a 3p electron, n=3 and l=1. The magnetic quantum number m_l can be -1, 0, or +1.
Correct Answer: B — n=3, l=1, m_l=1
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Q. Which of the following sets of quantum numbers corresponds to an electron in a 4d orbital?
-
A.
n=4, l=0, m_l=0
-
B.
n=4, l=2, m_l=1
-
C.
n=3, l=2, m_l=2
-
D.
n=4, l=1, m_l=0
Solution
For a 4d orbital, n=4 and l=2. The m_l value can be -2, -1, 0, +1, +2.
Correct Answer: B — n=4, l=2, m_l=1
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Q. Which of the following sets of quantum numbers is not allowed?
-
A.
n=2, l=1, m_l=0
-
B.
n=3, l=2, m_l=2
-
C.
n=1, l=0, m_l=1
-
D.
n=4, l=3, m_l=-3
Solution
For l=0, m_l can only be 0. Therefore, n=1, l=0, m_l=1 is not allowed.
Correct Answer: C — n=1, l=0, m_l=1
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Q. Which of the following sets of quantum numbers is not possible?
-
A.
n=3, l=2, m_l=1
-
B.
n=2, l=1, m_l=2
-
C.
n=4, l=3, m_l=0
-
D.
n=1, l=0, m_l=0
Solution
For l=1, m_l can only be -1, 0, or +1. Therefore, m_l=2 is not possible.
Correct Answer: B — n=2, l=1, m_l=2
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Q. Which of the following solutions has the highest boiling point?
-
A.
0.1 M NaCl
-
B.
0.1 M KCl
-
C.
0.1 M CaCl2
-
D.
0.1 M glucose
Solution
CaCl2 dissociates into 3 ions (Ca^2+ and 2 Cl^-), leading to the highest boiling point elevation among the options.
Correct Answer: C — 0.1 M CaCl2
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Q. Which of the following solutions has the highest concentration?
-
A.
0.1 M NaCl
-
B.
0.2 M KCl
-
C.
0.05 M CaCl2
-
D.
0.3 M MgSO4
Solution
Concentration in terms of molarity: 0.1 M NaCl = 0.1, 0.2 M KCl = 0.2, 0.05 M CaCl2 = 0.15 (0.05*3), 0.3 M MgSO4 = 0.3. Highest is 0.3 M MgSO4.
Correct Answer: D — 0.3 M MgSO4
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Q. Which of the following solutions will have the highest boiling point?
-
A.
0.1 M NaCl
-
B.
0.1 M KCl
-
C.
0.1 M glucose
-
D.
0.1 M MgCl2
Solution
0.1 M MgCl2 will have the highest boiling point due to the highest van 't Hoff factor (i = 3).
Correct Answer: D — 0.1 M MgCl2
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Q. Which of the following solutions will have the lowest freezing point?
-
A.
0.1 M NaCl
-
B.
0.1 M KBr
-
C.
0.1 M MgCl2
-
D.
0.1 M glucose
Solution
MgCl2 dissociates into 3 ions, leading to the greatest freezing point depression among the options.
Correct Answer: C — 0.1 M MgCl2
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Q. Which of the following solutions will have the lowest vapor pressure?
-
A.
0.1 M NaCl
-
B.
0.1 M KBr
-
C.
0.1 M MgCl2
-
D.
0.1 M glucose
Solution
MgCl2 dissociates into 3 ions, leading to the highest number of solute particles and thus the lowest vapor pressure.
Correct Answer: C — 0.1 M MgCl2
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Q. Which of the following species exhibits sp3d hybridization?
-
A.
SF4
-
B.
XeF2
-
C.
NH3
-
D.
C2H4
Solution
In SF4, the sulfur atom is sp3d hybridized, resulting in a seesaw molecular geometry.
Correct Answer: A — SF4
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Q. Which of the following species has a bond order of 1?
Solution
F2 has a bond order of 1, calculated as (8 bonding electrons - 6 antibonding electrons)/2 = 1.
Correct Answer: C — F2
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Q. Which of the following species has a central atom with sp3 hybridization?
-
A.
CCl4
-
B.
CO2
-
C.
BF3
-
D.
H2O
Solution
In CCl4, the central carbon atom is sp3 hybridized, forming a tetrahedral geometry.
Correct Answer: A — CCl4
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Q. Which of the following species has a linear geometry due to hybridization?
-
A.
H2O
-
B.
CO2
-
C.
NH3
-
D.
CH4
Solution
CO2 has a linear geometry due to the sp hybridization of the carbon atom.
Correct Answer: B — CO2
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Q. Which of the following species has a linear molecular geometry?
-
A.
BeCl2
-
B.
NH3
-
C.
H2O
-
D.
CH3Cl
Solution
BeCl2 has two bonding pairs and no lone pairs, resulting in a linear molecular geometry.
Correct Answer: A — BeCl2
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