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 displace its environment.

Front

What does a positive ΔH indicate?

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A positive ΔH indicates that a process is endothermic, meaning it absorbs heat from the surroundings.

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What does a negative ΔH indicate?

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A negative ΔH indicates that a process is exothermic, meaning it releases heat to the surroundings.

Front

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

Back

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

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What type of reaction is represented by the equation C(s, graphite) ⟶ C(s, diamond) ΔH=1.90kJ?

Back

This reaction is endothermic.

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What is the enthalpy change for the reaction 2NO + O2 → 2NO2 ΔH = -112kJ?

Back

The enthalpy change can be expressed as 2NO + O2 → 2NO2 + 112kJ.

Front

What is an exothermic reaction?

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An exothermic reaction is a chemical reaction that releases energy in the form of heat.

Front

What is an endothermic reaction?

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An endothermic reaction is a chemical reaction that absorbs energy from its surroundings.

Front

What is the significance of ΔH in chemical reactions?

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ΔH helps predict whether a reaction will absorb or release heat, influencing reaction spontaneity.

Front

How does temperature affect enthalpy?

Back

As temperature increases, the enthalpy of a substance generally increases due to increased kinetic energy.