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

How does enzyme enhance the rate of chemical reaction?

  1. By providing optimum temperature

  2. By lowering activation energy

  3. By producing ATP

  4. By raising the temperature
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Enzymes are capable of lowering the activation energy thereby bringing the reactants closer together into its active site allowing the chemical bonds to weaken and thereby leading to the formation of new bonds and thus a new product.

Multiple choice

Which of the following statements is/are false?

a. Spontaneous combustion never takes place at the room temperature. b. The heat required for spontaneous combustion is produced inside the substance by its slow oxidation. c. A large amount of gas is released quickly in an explosive combustion.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct option as this statement is false. Spontaneous combustion takes place at the room temperature.

Multiple choice

At high temperature, an enzyme is

  1. inactivated

  2. unaffected

  3. slightly activated

  4. denatured
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Enzymes are proteins with specific three-dimensional structures essential for their function. At high temperatures (usually above 40-45°C for human enzymes), the increased thermal energy disrupts the weak bonds (hydrogen bonds, van der Waals forces) maintaining this structure, causing the enzyme to denature. Denaturation is irreversible - the enzyme loses its active site shape and can no longer catalyze reactions.