All Free Chemistry MCQs with Answers
Every Chemistry question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
13,720 questions · page 669 of 686
- A. The energy absorbed when 1 mole of an ionic crystal lattice is formed from its constituent ions in the gaseous state.
- B. The energy liberated when 1 mole of an ionic crystal lattice is formed from its constituent ions in the gaseous state.
- C. The energy liberated when 1 mole of an ionic crystal lattice is split into its constituent ions in the gaseous state.
- D. None of the above
Explanation: Lattice energy refers to the energy change associated with the formation of an ionic solid from its gaseous ions.
Correct answer: The energy liberated when 1 mole of an ionic crystal lattice is formed from its constituent ions in the gaseous state.- A. Haber process
- B. Born Haber cycle
- C. Hess's law
- D. Enthalpy changes
Explanation: The answer is Haber process because it is the process of formation of ammonia from nitrogen and hydrogen under high pressure.
Correct answer: Haber process- A. A decrease in the volume of the container .
- B. An increase pressure by addition of hydrogen
- C. Removal of NH3
- D. An increase in pressure by addition.of nitrogen
Explanation: To do such questions, Your concepts about the Le Chatelier principle must be clear and you must know how to apply that.
Correct answer: An increase in pressure by addition.of nitrogen13364. In the given Exothermic reaction PCl3 + Cl2 (g) ➔PCl5(g) an increase in yield will be favoured by:
- A. Decrease of temperature
- B. Increase of temperature
- C. Keeping temperature constant
- D. None of these
Explanation: Since the forward reaction is exothermic, decreasing the temperature will cause the reaction to shift in the forward direction by Le…
Correct answer: Decrease of temperature- A. Both pressure and temperature are increased
- B. Both pressure and temperature are decreased
- C. Temperature is decreased and pressure is increased
- D. Temperature is increased and pressure is increased
Explanation: The reaction 2SO2 + O2 → 2SO3 is exothermic, releasing heat. According to Le Chatelier's principle, increasing pressure shifts the…
Correct answer: Temperature is decreased and pressure is increased- A. Is independent of temperature
- B. Increases as temperature increases
- C. Decreases as temperature increases
- D. Varies with the addition of N2 and O2
Explanation: In general, for an exothermic reaction, the reaction rate decreases as the temperature increases.
Correct answer: Decreases as temperature increases- A. Increase in temperature
- B. Decrease in temperature
- C. No change in temperature
- D. First increase and then decrease in temperature
Explanation: Increasing the temperature of the system provides more heat energy to the reaction, which helps drive the reaction toward the reactant side.
Correct answer: Increase in temperature- A. Endothermic process
- B. Exothermic process
- C. Vaporization process
- D. Change of H2O into O2 and H2
Explanation: The ionic product of water (Kw) is the product of the concentrations of hydrogen ions (H+) and hydroxide ions (OH-) in water.
Correct answer: Endothermic process- A. The equilibrium will shift in the backward direction
- B. The equilibrium position will remain unchanged
- C. The equilibrium will shift in the forward direction
- D. All of the above
Explanation: In an endothermic reaction such as N2(g) + O2(g) → 2NO(g), increasing the temperature provides additional heat that the system can absorb.
Correct answer: The equilibrium will shift in the forward direction- A. Forward direction
- B. Reverse direction
- C. To all system at equilibrium
- D. None of the above
Explanation: By increasing the pressure, the equilibrium between ice and water will shift in the direction of the phase with the lower volume, which is…
Correct answer: Forward direction- A. N2
- B. H2
- C. both (a) & (b)
- D. None of these
Explanation: The balanced chemical equation for the production of ammonia is: N2 + 3H2 → 2NH3.
Correct answer: N2- A. N2
- B. H2
- C. Both a & b
- D. None of them
Explanation: The balanced chemical equation for the formation of ammonia (NH3) is:N2 + 3H2 → 2NH3You start with 28.0 g of N2 and 8.0 g of H2.
Correct answer: N2- A. N2
- B. H2
- C. Ammonia
- D. None of the above
Explanation: The balanced equation is shown below. N2 (g)+ 3H2 (g) → 2NH3 (g) If equal moles of each reactant are used, hydrogen will be the limiting…
Correct answer: H2- A. XeF6, 25.5 g
- B. SiO2, 26 g
- C. XeF6, 52 g
- D. SiO2, 52 g
Explanation: To solve this problem, first calculate the moles of each reactant. For XeF6, with a molar mass of 245.3 g/mol, 122.6 g is equivalent to…
Correct answer: XeF6, 25.5 g- A. Oxygen gas
- B. Liquid ethanol
- C. Both A and B
- D. None of the above
Explanation: The heating reagent in this reaction is oxygen gas. When ethanol and oxygen gas are sparked together, they undergo a combustion reaction…
Correct answer: Oxygen gas- A. Liquid ethanol
- B. Oxygen gas
- C. Both (A) and (B)
- D. None of the stove
Explanation: So, in the reaction between liquid ethanol and oxygen gas, we need to figure out which one is the limiting reagent.
Correct answer: Liquid ethanol- A. H2 is the excess agent
- B. O2 is the limiting agent
- C. H2 is the limiting reagent
- D. The reaction has no limiting reagent
Explanation: Option C is the correct answer. In the reaction 2H2 + O2 --> 2H2O, we start with 5 moles of both hydrogen and oxygen.
Correct answer: H2 is the limiting reagent- A. 4.5 x 10^23
- B. 3.6 x 10^24
- C. 2.7 x 10^24
- D. 9.0 x 10^23
Explanation: In one molecule of aluminum carbonate, there are 3 molecules of carbonate ions, which have 3 oxygen atoms each so there are 9 atoms of…
Correct answer: 2.7 x 10^24- A. 0.643
- B. 0.779
- C. 28.0
- D. 1.28
Explanation: 1 mole: 58.5 g of NaCl x mole: 75 g of NaCl x=1.28
Correct answer: 1.28- A. HN2
- B. NH3
- C. HN3
- D. NH2
Explanation: H N Moles: 0.1/1 4.20/14Divide by the smallest number calculated : 0.1/0.1 0.3/0.1Answer: 1 3HN3
Correct answer: HN3