I would agree with the second one, not the first. You can't always see the chemical reaction, and it isn't always sudden. But the second claim is true.
Answer:
Subtract the mass of the CuSO4⋅ 5H2O from the mass of CuSO4 is the right one
Answer:
Here just look at the pic here
Explanation:
Multiply the volume by the density. 1 ml = 1 cm^3
1.11 g/cm^3 * 1 cm^3/mL * 386 mL = 428 g
All your units cancel out except for g which is what you would expect since you want units of mass.