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

Dec 5, 2016

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: