Enthalpy

Front

What is Enthalpy?

Back

Enthalpy (H) is a measure of the total energy of a thermodynamic system, including internal energy and the energy required to make room for it by displacing its environment.

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 sign of ΔH for an exothermic reaction?

Back

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

Front

What is the sign of ΔH for an endothermic reaction?

Back

The sign 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

In the reaction C + O2 → CO2 + 60kJ, what is ΔH?

Back

ΔH = -60 kJ, indicating the reaction is exothermic.

Front

For the reaction 2NO + O2 → 2NO2, if ΔH = -112 kJ, what does this imply?

Back

This implies that the reaction releases 112 kJ of energy, making it exothermic.

Front

Which process has a positive ΔH?

Back

Water boiling and dry ice sublimating both have a positive ΔH, indicating they absorb heat.

Front

What is the relationship between enthalpy and temperature?

Back

As temperature increases, the enthalpy of a substance generally increases, as more energy is required to maintain higher temperatures.

Front

What is an example of an exothermic reaction?

Back

The reaction of hydrochloric acid with sodium hydroxide, producing water and sodium chloride, is an example of an exothermic reaction.