The answer is C, because if the copper has a +2 charge, the fluoride must have a -2 charge in order to cancel out.
its 40
I just took the test right now to get this answer
Answer:
I guess B They have a charge
Answer:

Explanation:
First of all we need to calculate the heat that the water in the cooler is able to release:

Where:
- Cp is the mass heat capacity of water
- V is the volume
is the density


To calculate the mass of CO2 that sublimes:

Knowing that the enthalpy of sublimation for the CO2 is: 

