a) MCaCl2= ACa+2ACl=40+2*35,5=111g/mol
n=m/M=>m=n*M=0,25*111=27,75g CaCl2
b) MCaCO3=100kg/kmol
m=n*M=7,5*100=750kg CaCO3
c) 1 mol Cl2....................6,022*10^23 molecule Cl2
x....................................0,0009033*10^23 molecule Cl2
x=0,0009033/6,022=0,00015 moli Cl2
m=n*M=0,00015 * 71=0,01065g Cl2