CHEMISTRY COMMUNITY

Under what circumstances would delta H be equal to delta U? Can someone explain this? In the notes we wrote that the volume of the reactants would be equal to the volume of the products if pressure was constant. However, I still don't get how delta H then becomes equal to delta U

Delta H would be equal to Delta U when there is no work being done.
No work is being done when volume is constant or if there is no external pressure (vacuum)