The material that will be able to pass the cell, would be characterized as being soluble. As in order for them to pass, they would be able to dissolve in one of the layers of the membrane, I believe.
I believe the answer is "hard water"
The enthalpy change for the formation of hydrogen peroxide from water and oxygen is +98.2 kJ·mol⁻¹.
The negative sign tells you that the reaction <em>releases energy</em>.
To make the reaction go in the reverse direction, you must put the same amount of energy back into the system.
Thus, you simply <em>reverse the sign</em> of the enthalpy change for the forward direction.
the answer is 4. a scientific law is often based in the scientific community
