Chemistry (School & UG)

Q. In a constant pressure process, the work done by the system is given by which equation?
  • A. W = PΔV
  • B. W = ΔH
  • C. W = ΔU
  • D. W = Q + ΔH
Q. In a coordination compound, what does the term 'coordination number' refer to?
  • A. The number of ligands attached to the metal ion
  • B. The total number of electrons in the complex
  • C. The oxidation state of the metal ion
  • D. The number of unpaired electrons in the metal
Q. In a Daniell cell, which electrode is the anode?
  • A. Copper electrode
  • B. Zinc electrode
  • C. Silver electrode
  • D. Lead electrode
Q. In a Daniell cell, which species is reduced?
  • A. Zn
  • B. Cu²⁺
  • C. Zn²⁺
  • D. Cu
Q. In a first-order reaction, if the half-life is 10 minutes, what is the rate constant?
  • A. 0.0693 min^-1
  • B. 0.1 min^-1
  • C. 0.693 min^-1
  • D. 0.5 min^-1
Q. In a first-order reaction, if the half-life is 10 minutes, what will be the half-life if the initial concentration is doubled?
  • A. 10 minutes
  • B. 20 minutes
  • C. 5 minutes
  • D. 15 minutes
Q. In a first-order reaction, if the half-life is 10 minutes, what will be the half-life if the concentration is doubled?
  • A. 10 minutes
  • B. 20 minutes
  • C. 5 minutes
  • D. It cannot be determined
Q. In a flame test, which color indicates the presence of sodium ions?
  • A. Green
  • B. Red
  • C. Yellow
  • D. Blue
Q. In a galvanic cell, which electrode is the site of reduction?
  • A. Anode
  • B. Cathode
  • C. Salt bridge
  • D. Electrolyte
Q. In a galvanic cell, which reaction occurs at the anode?
  • A. Reduction
  • B. Oxidation
  • C. Neutralization
  • D. Hydrolysis
Q. In a molecule with a triple bond, how many sigma and pi bonds are present?
  • A. 1 sigma, 2 pi
  • B. 2 sigma, 1 pi
  • C. 3 sigma, 0 pi
  • D. 0 sigma, 3 pi
Q. In a nucleophilic substitution reaction, what is the role of the solvent?
  • A. To stabilize the nucleophile
  • B. To stabilize the leaving group
  • C. To provide a medium for the reaction
  • D. To increase the reaction rate
Q. In a phase diagram, what does the line between the solid and liquid phases represent?
  • A. Sublimation point
  • B. Melting point
  • C. Boiling point
  • D. Triple point
Q. In a qualitative analysis using paper chromatography, which factor primarily affects the Rf value of a substance?
  • A. Solvent polarity
  • B. Temperature
  • C. pH of the solution
  • D. Molecular weight
Q. In a reaction at equilibrium, what effect does adding an inert gas at constant volume have?
  • A. Shifts the equilibrium to the right
  • B. Shifts the equilibrium to the left
  • C. No effect on the equilibrium
  • D. Increases the reaction rate
Q. In a reaction at equilibrium, what effect does increasing the temperature have on an exothermic reaction?
  • A. Shifts equilibrium to the right
  • B. Shifts equilibrium to the left
  • C. No effect on equilibrium
  • D. Increases the rate of reaction
Q. In a reaction at equilibrium, what happens if the concentration of a reactant is increased?
  • A. The equilibrium shifts to the right
  • B. The equilibrium shifts to the left
  • C. The equilibrium remains unchanged
  • D. The reaction stops
Q. In a reaction at equilibrium, what happens if the pressure is increased by decreasing the volume?
  • A. Shifts to the side with more moles of gas
  • B. Shifts to the side with fewer moles of gas
  • C. No effect
  • D. Reaction stops
Q. In a reaction at equilibrium, what happens if the volume is increased?
  • A. Shifts to the side with more moles of gas
  • B. Shifts to the side with fewer moles of gas
  • C. No effect
  • D. Reaction stops
Q. In a reaction at equilibrium, what happens to the concentrations of reactants and products?
  • A. They remain constant
  • B. They increase
  • C. They decrease
  • D. They fluctuate
Q. In a reaction at equilibrium, what happens to the enthalpy if the temperature is increased?
  • A. Enthalpy increases for exothermic reactions
  • B. Enthalpy decreases for endothermic reactions
  • C. Enthalpy increases for endothermic reactions
  • D. Enthalpy remains unchanged
Q. In a reaction at equilibrium, what is the effect of increasing the pressure if the number of moles of gas is equal on both sides?
  • A. Shifts equilibrium to the right
  • B. Shifts equilibrium to the left
  • C. No effect on equilibrium
  • D. Increases the reaction rate
Q. In a reaction mechanism, what is an intermediate?
  • A. A reactant that is consumed in the final product
  • B. A product that is formed and then consumed
  • C. A catalyst that speeds up the reaction
  • D. A transition state of the reaction
Q. In a reaction mechanism, what is the term for a species that is formed in one step and consumed in a subsequent step?
  • A. Intermediate
  • B. Catalyst
  • C. Transition state
  • D. Reactant
Q. In a reaction mechanism, what is the term for the slowest step that determines the overall reaction rate?
  • A. Rate-determining step
  • B. Intermediate step
  • C. Fast step
  • D. Equilibrium step
Q. In a reaction where heat is absorbed (endothermic), what happens if the temperature is decreased?
  • A. Shifts to the right
  • B. Shifts to the left
  • C. No effect
  • D. Reaction rate decreases
Q. In a reaction where heat is absorbed (endothermic), what happens when the temperature is decreased?
  • A. Shifts to the right
  • B. Shifts to the left
  • C. No effect
  • D. Increases the reaction rate
Q. In a reaction where the rate constant doubles with a 10°C increase in temperature, what is the approximate activation energy (Ea) if R = 8.314 J/(mol·K)?
  • A. 40 kJ/mol
  • B. 80 kJ/mol
  • C. 120 kJ/mol
  • D. 160 kJ/mol
Q. In a reaction with a rate constant of 0.03 s^-1, how long will it take for the concentration to decrease to 25% of its initial value?
  • A. 23.1 s
  • B. 46.2 s
  • C. 69.3 s
  • D. 92.4 s
Q. In a redox reaction, if the oxidation state of manganese changes from +7 to +2, how many electrons are gained?
  • A. 5
  • B. 3
  • C. 2
  • D. 7
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