The type of chemical reaction that causes sucrose to break up into simpler units is called hydrolysis.

Here's why:

* Sucrose is a disaccharide, meaning it's made up of two simpler sugar units: glucose and fructose.

* Hydrolysis is a reaction where water (H₂O) is added to break a chemical bond. In the case of sucrose, the water molecule splits the bond between glucose and fructose.

The reaction can be represented as:

Sucrose + H₂O → Glucose + Fructose

Key takeaway: Hydrolysis is the process responsible for breaking down complex sugars like sucrose into their simpler components.