Understanding Enthalpy and Thermodynamics

What is internal energy defined as?

• The sum of kinetic and potential energy

• Only the potential energy of particles

• The difference between kinetic and potential energy

• Only the kinetic energy of particles

Why can't we find the absolute value of internal energy?

• Because it is a constant value

• Because it is a relative measure

• Because it depends on external factors

• Because it is always zero

In an isothermal process for an ideal gas, what is the internal energy?

• Equal to kinetic energy

• Equal to potential energy

• Equal to the sum of kinetic and potential energy

• Zero

What does enthalpy include?

• Neither internal energy nor work done

• Only internal energy

• Only work done

• Internal energy and work done

What happens when enthalpy is positive?

• The process does not involve heat

• The process is endothermic

• The process is at equilibrium

• The process is exothermic

How is enthalpy change calculated at constant pressure?

• ΔH = ΔV + PΔU

• ΔH = ΔP + VΔU

• ΔH = ΔU + PΔV

• ΔH = ΔU + VΔP

What does an extensive property mean in the context of enthalpy?

• It depends on the path taken

• It is always constant

• It is independent of the amount of substance

• It depends on the amount of substance

What is the relationship between enthalpy and the first law of thermodynamics?

• ΔH = Q at constant pressure

• ΔH = Q at constant volume

• ΔH = W at constant volume

• ΔH = W at constant pressure

In the first law of thermodynamics, what does the negative sign in work done indicate?

• Work is done on the system

• No work is done

• Work is constant

• Work is done by the system

What is the enthalpy change if the internal energy change is 50 liter atmosphere and the pressure-volume work is 26 liter atmosphere?

• 100 liter atmosphere

• 76 liter atmosphere

• 50 liter atmosphere

• 24 liter atmosphere