Your control group would be the batteries since you CONTROL what brand you're using, for which one lasts the longest...aren't you suppose to figure that out when you do the experiment?
The molar mass of the hydrate is 278.06
The molar mass of the anhydrous salt is 151.92
The molar mass of water in the hydrate is 126.14
Explanation:
Molarity = mol/L or g/L
Data:
Mass>80.0g
Mr of CaCl2>111.1g/mol
V>500mL
Convert mL to Litres;. mole=g/Mr
1L=1000mL. =80g/111.1g/mol
x=500mL. =0.720072007mol
x=0.5L
Molarity= mole/volume
=0.720072007mol/0.5L
=1.440144014mol/L
=1.4401mol/L
Hope this helps. Depending on the question you can also find it in g/L but mol/L is safer.
