Answer:
water has several important physical properties. Most of the physical properties of water are quite atypical e.g molar mass is 18.0151grams per mol and melting point is 0.00 degree
The mass of one mole of water it is 18 amu, but you need to find the mass of a molecule of water, therefore you calculate the mass of one mole of water, which is 18 amu and you divided by Avogadro's number which is 6,022 x 10^23. The result is 2,989 x 10^-23. Hope I helped you. If you have any questions ask :) Good luck.
Adding more powdered reactants
Cobalt sulphate is the usual source of water-soluble cobalt since it is the most economical salt and shows less tendency to deliquesce or dehydrate