Answer:
0.011 moles
Explanation:
There are about 6.02*10^23 atoms in a mole, so in the given sample, there are

which is about 0.011 moles.
Hi there!
It can take years to remove all of the harmful substances from the water.
I hope my answer helped :)
Molar mass of water 18g/mol
Number of mols = 50.0g/18g/mol =2.78 mol
Heat absorbed = 40.7 kj/mol * 2.78 mol = 113.1 kj.