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 504 of 686
- A. Surrounding from the environment
- B. Reactants from contamination
- C. System from surrounding
- D. Products from the surrounding
Explanation: In thermodynamics, a boundary separates a system from its surroundings. A system is a collection of matter and energy that is under study.
Correct answer: System from surrounding- A. Surroundings
- B. System
- C. State of a system
- D. All of these
Explanation: In thermodynamics, the state of a system is described by a set of properties that define its condition at a given point in time.
Correct answer: State of a system- A. Water
- B. Water in cup
- C. Whole table
- D. All of these
Explanation: In thermodynamics, a state of matter that is confined by some walls in space and separated from surroundings by those walls is called a…
Correct answer: Water- A. AI2O3
- B. B2O3
- C. CO
- D. All of these
Explanation: Standard enthalpies of formation (∆Hf) for certain compounds, such as Al2O3 (aluminum oxide), B2O3 (boron oxide), and CO (carbon…
Correct answer: All of these- A. Spontaneous reaction
- B. Exothermic reaction
- C. Endothermic reaction
- D. Non-spontaneous reaction
Explanation: A reaction that does not occur in nature is often referred to as a "non-spontaneous" or "non-natural" reaction.
Correct answer: Non-spontaneous reaction- A. Route taken by reaction for completion
- B. Temperature of reactants
- C. Concentration of products
- D. Concentration of reactants
Explanation: Hess's law states that the total enthalpy change of a reaction remains the same regardless of the route taken by the reaction for…
Correct answer: Route taken by reaction for completion10067. For a reaction that can takes place in more than one ways, the enthalpy of that reaction is _?
- A. Same for all the routes of that reaction
- B. Different for different routes of that reaction
- C. Depends up on the reactants present in each route
- D. None of these
Explanation: Option A is correct since it states the correct definition of Hess's law which is: If a chemical change takes place by several different…
Correct answer: Same for all the routes of that reaction10068. Knowledge obtained through thermodynamics is used to explain which of the following property?
- A. Boiling point
- B. Chemical bonding
- C. Quantum study
- D. Physical properties
Explanation: Knowledge obtained through thermodynamics is used to explain: d) Physical properties Thermodynamics provides insights and explanations for…
Correct answer: Physical properties- A. Unity
- B. Zero
- C. Positive
- D. Negative
Explanation: In a cyclic process the net change in internal energy is zero because the system returns to its initial state.
Correct answer: Zero- A. Exothermic reaction
- B. Endothermic reaction
- C. Spontaneous reaction
- D. Non spontaneous reaction
Explanation: The term exothermic process describes a process or reaction that releases energy from the system to its surroundings, usually in the form…
Correct answer: Exothermic reaction- A. Done by temperature change
- B. Pressure - Temperature Work
- C. Pressure - Volume Work
- D. None of these options is correct
Explanation: The work is pressure-volume work. Pressure-volume work is the work that is done by the compression or expansion of a fluid.
Correct answer: Pressure - Volume Work- A. Joule/mole
- B. kJ/mole
- C. kJ mol
- D. All options are correct.
Explanation: Joule is defined as 1kgm2s-2. Joule is a small quantity of energy, hence chemists usually express it in kJ.
Correct answer: kJ/mole- A. Heat remains constant
- B. Heat is lost
- C. Heat is absorbed
- D. No heat gain or lose takes place
Explanation: Option C is correct since, in an endothermic reaction, the products are higher in energy than the reactants.
Correct answer: Heat is absorbed- A. Enthalpy of Formation
- B. Enthalpy of Neutralization
- C. Enthalpy of Atomization
- D. Enthalpy of Reaction
Explanation: The given reaction ½ H2 → H represents the dissociation of hydrogen molecule into hydrogen atoms, and the enthalpy change associated with…
Correct answer: Enthalpy of Atomization- A. Enthalpy
- B. Internal energy
- C. Thermal energy
- D. Temperature
Explanation: Heat is not a thermodynamic property because heat is the energy that is transferred due to a temperature difference, which means that heat…
Correct answer: Thermal energy- A. Damages ... intolerable
- B. Ambiguities ...superior
- C. Shortcomings ...shoddy
- D. Occurrences ...attractive
Explanation: The sentence can be completed with the following words:"Shortcomings" and "shoddy" So the completed sentence is:"The foreman's clemency…
Correct answer: Shortcomings ...shoddy- A. 2
- B. -1
- C. 5
- D. 4
Explanation: The given sequence is: 2, -1, 2, -1, 2, ?. The pattern here is an alternating one: every second term is the same.
Correct answer: -1- A. If statement I is the cause and statement II is its effect;
- B. If statement II is the cause and statement. I is its effect;
- C. If both the statements I and II are independent causes;
- D. If both the statements I and II are effects of independent causes;
- E. If both the statements I and II are effects of some common cause;
Explanation: Statement II highlights the lack of parks in the locality, which is a plausible reason for the protest described in Statement I.
Correct answer: If statement II is the cause and statement. I is its effect;- A. If only I follows
- B. If only II follows
- C. If either I or II follows
- D. If neither I nor II follows
- E. If both I and II follow
Explanation: The statement indicates that the local government has agreed to provide necessary infrastructural facilities for the trust's clean water…
Correct answer: If both I and II follow- A. P
- B. V
- C. q
- D. H (enthalpy)
Explanation: A state function is a property of a system that depends only on the current state of the system, not on the path by which the system…
Correct answer: q