Question

What is a chemical reaction that absorbs heat from the surrounding? Does this reaction have a neutral, positive or negative `DeltaH` at constant pressure?

Answer 1

Negative

Explanation:

#ΔH # is change in enthalpy.

When energy is input into the system (heat) #ΔH # will have a positive value.

Positive values of #ΔH # tell us that energy was input into the system, breaking constituent chemical bonds.

When #ΔH # is negative, this means that bonds were formed and that the system has released energy into the universe.

Consider the graphic below where #ΔH # is negative: