Question

When magnesium chloride (MgCl2) dissolves in water, it dissociates into magnesium ions and chloride ions. how many chloride ions form when a 42.66 gram sample of magnesium chloride is dissolved in water?

a) 2.70 x 10^23
b) 8.09 x 10^23
c) 5.39 x 10^23
d) 2.69 x 10^24

Answer 1

A 42.66-gram sample of magnesium chloride will dissolve in water to produce 0.448 moles of ions (option A).

How many moles are there, exactly?

In response to this query, magnesium chloride (MgCl2) separates into magnesium ions and chloride ions when it dissolves in water.

Mg2+(aq) + Cl MgCl2(aq) (aq)

However, if a 42.66-gram sample of magnesium chloride dissolves in water, the number of moles of the ionic products will be 42.66 g/molecular mass of MgCl2.

MgCl2 has a molecular weight of 95.3 g/mol.

mol = 42.66g x 95.3g/mol = 0.448mol

Therefore, when a 42.66-gram sample of magnesium chloride is dissolved in water, 0.448 moles of ions will result.