Enthalpy

Front

What is enthalpy?

Back

Enthalpy (H) is a thermodynamic quantity that represents the total heat content of a system, defined as the internal energy plus the product of pressure and volume (H = U + PV).

Front

What does ΔH represent in a chemical reaction?

Back

ΔH represents the change in enthalpy during a chemical reaction, indicating whether the reaction absorbs or releases heat.

Front

What is the value of ΔH for an exothermic reaction?

Back

The value of ΔH for an exothermic reaction is negative, indicating that heat is released.

Front

What is the value of ΔH for an endothermic reaction?

Back

The value of ΔH for an endothermic reaction is positive, indicating that heat is absorbed.

Front

What is specific heat?

Back

Specific heat is the amount of energy required to raise the temperature of 1 gram of a substance by 1°C.

Front

What is the SI unit of heat and energy?

Back

The SI unit of heat and energy is the joule (J).

Front

What happens to the enthalpy of a system when it absorbs heat?

Back

When a system absorbs heat, its enthalpy increases, resulting in a positive ΔH.

Front

What happens to the enthalpy of a system when it releases heat?

Back

When a system releases heat, its enthalpy decreases, resulting in a negative ΔH.

Front

What is the enthalpy change for the reaction C + O2 -> CO2 + 60 kJ?

Back

The enthalpy change (ΔH) for the reaction is -60 kJ.

Front

Which process has a positive ΔH: Water boiling or Dry ice sublimating?

Back

Both water boiling and dry ice sublimating have a positive ΔH.