Thermodynamics | MCQs

Explanation

1 kilowatt hour (kWh) = 1000 watts × 3600 seconds

1 kWh = 1,000 × 3,600 = 3,600,000 joules (J)

Explanation

A reaction in which heat is absorbed is called an endothermic reaction.

These reactions lower the temperature of their surrounding area, thereby creating a cooling effect.

Explanation

As ice cream melts, it absorbs thermal energy from the surroundings, but its internal thermal energy decreases as it changes from solid to liquid.

This is a physical change.

Explanation

Explanation

• An Exothermic Reaction is a chemical reaction that releases or gives off heat, often accompanied by light, sound, or other forms of energy.
• This type of reaction involves a decrease in the system's energy, which is released into the surroundings as heat.

Explanation

Heat is a form of energy, specifically thermal energy, which is transferred from one body to another due to a temperature difference.

It is a type of kinetic energy, where the particles of a substance vibrate or move rapidly, generating heat.

Explanation

The equilibrium constant, Kc, for the reaction:

N2 + O2 ⇌ 2NO is unitless (No unit).

Since the number of moles of gas is the same on both the reactant and product sides (2 moles).

The concentration terms in the equilibrium constant expression cancel out, leaving Kc without units.

Explanation

Standard enthalpy change is measured at a defined pressure of 101 kPa (or 1 bar, according to Testbook.com) and a temperature of 298 K (25°C). 

Explanation

The triple point of water is the unique temperature and pressure at which water coexists in all three phases — solid, liquid, and gas — in equilibrium.

Temperature: 273.16 Kelvin

This is used as a fundamental fixed point in defining the Kelvin temperature scale.

Explanation

For a diatomic gas (like O₂ or N₂), the ratio of specific heats 𝐶𝑝/𝐶𝑣 is approximately 1.4.

This ratio is also known as the adiabatic index (γ).

It is used in thermodynamic processes.