Asample containing 0.213g cl- is dissolved in 50.0ml of water how many moles of cl- are in the solution?

There are 0.006 moles of Cl- in the solution.

Explanation:

To solve this problem you should think in te concept of molar mass, the molar mass of Cl- is 35.45 grs/mol (it has the same mass as Cl, because electrons doesn´t contribute with significant mass). So,

35.45 grs 1 mol Cl-

0.213 grs   x = 0.006 moles Cl-

There are 0.006 moles of Cl- in the solution.

i think it is true since you can test the answer and can use observations to complete it.

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.