Chemistry · Physics

Thermodynamics and Chemical Kinetics

1,132 Questions

Thermodynamics and chemical kinetics are crucial branches of physical chemistry. This area focuses on energy transformations, reaction rates, equilibrium constants, and catalysts. These topics carry significant weight in competitive science and engineering examinations.

Enthalpy and energyChemical equilibriumEntropy conceptsReaction kinetics and catalysts

Thermodynamics and Chemical Kinetics Questions

Multiple choice chemistry change around us physical changes changes and their classification physical changes

In a physical change :

  1. new substances are not formed

  2. reaction is reversible

  3. change is temporary

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Physical changes in a substance do not form new substances, these reactions are reversible and the change is temporary.

Physical changes are the changes affecting the form of a chemical substance, but not its chemical composition. They are used to separate mixtures into their component compounds, but cannot usually be used to separate compounds into chemical elements or simpler compounds.

Multiple choice chemistry basic concepts of chemistry law of multiple proportion law of multiple proportions laws of chemical combination

A chemical equation is balanced according to the law of: 

  1. multiple proportions

  2. constant proportions

  3. reciprocal proportions

  4. conservation of mass
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
When we balance an equation, we determine the ratio of reactants to products which allows for the total number of atoms of reactants to match the number of atoms of the products.

 Since the type of atoms does not change and the number of atoms stays that same, the total mass that goes into the chemical change will match the mass that comes out after the change.

   So, law of conservation of mass is the correct answer.
Multiple choice physics the essence of change forms of energy and energy conservation energy for everything forms of energy

The energy present in petrol is :

  1. Chemical

  2. Kinetic

  3. Potential

  4. Heat
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 chemical energy is the potential of a chemical substance to undergo a transformation through a chemical reaction to transform other chemical substances.

kinetic energy is due to motion.
potential energy is due to relative position.
heat energy is due to temperature.
in petrol different different reaction occurs which provide energy to run the engine, so energy possessed in petrol is chemical energy.
option A.

Multiple choice physics the essence of change forms of energy and energy conservation energy for everything forms of energy

What is potential energy?

  1. Energy of an abject due to its position or arrangement in a system

  2. Energy of an abject due to its nature or arrangement in a system

  3. Energy of an abject due to its shape or arrangement in a system

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Energy of an abject due to its position or arrangement in a system is potential energy. 

Multiple choice physics the essence of change forms of energy and energy conservation energy for everything forms of energy

Identify, which of the following energies can be positive only:

  1. Kinetic energy

  2. Potential energy

  3. Mechanical energy

  4. Both kinetic and mechanical energies.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Potential energy is the energy stored by the virtue of the position of a body.While,kinetic energy is the energy possessed by the virtue of motion.
Hence, K.E is always +ve .
When a body is raised to a particular height,work is done against the force of gravity and P.E is $ - $ve.
When the body is falling freely the work is done in the direction of force of gravity and P.E is $+$ ve.

Multiple choice physics the essence of change forms of energy and energy conservation energy for everything forms of energy

Identify, which of the following energies can be positive only

  1. kinetic energy

  2. potential energy

  3. mechanical energy

  4. both kinetic and mechanical energies
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Only kinetic energy can have positive value. Potential energy has negative value and mechanical energy is combination of these two hence can either be positive or negative.

Multiple choice physics the essence of change forms of energy and energy conservation energy for everything forms of energy

Energy stored in the bonds of molecules is a form of:

  1. heat energy

  2. potential energy'

  3. chemical energy

  4. light energy
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Energy that gets released when the bonds are formed was stored in the electromagnetic fields inside of the atom. When the bond is formed, the electrons and protons assume a configuration that has an, overall, less intense combination of electric and magnetic fields inside of the bonded atoms than when they were separate. 

Multiple choice chemistry energetics and thermochemistry bond energies and enthalpy changes bond enthalpies enthalpies for different types of reactions

The incorrect statement is :

  1. $ \Delta _{ So| }H^{ 0 }={ \Delta } _{ Lattice }H^{ 0+ }\Delta _{ Hyd }H^{ 0 } $

  2. The enthalpy on dilution is independent on original concentration.
  3. $ N \equiv N > C \equiv N > C \equiv C $ [value of mean bond enthalpy in KJ/mol]
  4. $ H _2O(S) \overset { 1\quad bar }{ \rightleftharpoons } H _2O(I) 273 K $


    $ \Delta U= +Ve; \Delta H = +ve; W= +ve; q = +ve $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The statement about dilution enthalpy is incorrect because enthalpy of dilution DOES depend on the original concentration of the solution. Dilution from different starting concentrations releases different amounts of heat. The other statements are correct: Born-Haber cycle relation, bond enthalpy order (N≡N=946 kJ/mol > C≡N=891 > C≡C=619), and ice melting thermodynamics.

Multiple choice chemistry energetics and thermochemistry bond energies and enthalpy changes bond enthalpies enthalpies for different types of reactions

Which of the following relationships is not correct?

  1. $\Delta H = \Delta E + \Delta n _gRT$
  2. $\Delta H _{sub} = \Delta H _{fusion} + \Delta H _{vap}$
  3. $\Delta H _r^0 = \sum H _{f(reactants)}^0 - \sum H _{f(products)}^0$
  4. $\Delta H _r^0 = \sum B.E. $ of reactants $- \sum B.E. $ of products
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

From definition of Heat of Formation and Hess' law, $\Delta H _r^0 = \sum H _{f(products)}^0 - \sum H _{f(reactants)}^0$

Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

What is the relationship between the kinetic energy($K$), potential energy($P$) and total energy($E$) of a system?

  1. $K=P+E$
  2. $E=P+K$
  3. $P=K+E$
  4. $E=PK$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total mechanical energy of the system is equal to the sum of kinetic energy of the system and the potential energy of the system.

Thus, total mechanical energy  $E = K+P$

Multiple choice biology coal, petroleum and petrochemicals carbon cycling mineral coal carbon cycle coal and its products

Which of the following conditions regarding a chemical process ensures its spontaneity at all temperature ? 

  1. $\Delta A > 0, \Delta S < 0$
  2. $\Delta H < 0, \Delta S > 0$
  3. $\Delta H < 0, \Delta S < 0$
  4. $\Delta H > 0, \Delta S > 0$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For a process to be spontaneous at all temperatures, the Gibbs free energy change (delta G = delta H - T*delta S) must be negative. This occurs when delta H is negative (exothermic) and delta S is positive (increase in entropy).

Multiple choice chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

Intensity of reaction of a metal with water depends upon its :

  1. mass number of metal

  2. chemical reactivity

  3. atomic no. of metal

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Metals react with water to form a metal hydroxide or metal oxide and hydrogen gas. Intensity of reaction depends upon its chemical reactivity.