Density can be calculated using the following rule:
density=mass/volume
therefore,
volume=mass/density
we have mass=0.451g and density=0.824g/ml
substituting in the above equation, we can calculate the volume as follows:
volume = 0.451/0.824 = 0.547 ml
(a)The change in Gibbs free energy for the reaction has been 2.6 kJ/mol.
(b) The change in Gibbs free energy for the reaction has been -49.3 kJ/mol.
(c) The change in Gibbs free energy for the reaction has been 91.38 kJ/mol.
I'm pretty sure your answer should be CaCl2. Hope this helps! =^-^= (if I need to explain more just let me know.)