Answer:
-20.1 degrees Celsius
Step-by-step explanation:
The system started at -12.6 Celsius. It then cooled 7.5 degrees during a reaction. Because it cooled, that means the difference is negative.
-12.6 degrees Celsius - 7.5 degrees Celsius = -20.1 degrees Celsius
It is important to always remember your correct names and variables for numbers in chemistry!
