How many moles of ions are released when this sample dissolves in water?

26.4 g of Ba(OH)2·8H2O

ytu6

To determine the number of moles of ions released when 26.4 g of Ba(OH)2·8H2O dissolves in water, we need to first understand the chemical formula of the compound.

Ba(OH)2·8H2O indicates that there are 2 hydroxide ions (OH-) for 1 barium ion (Ba2+), and there are also 8 water molecules (H2O) attached to each Ba(OH)2 unit.

To calculate the moles of Ba(OH)2·8H2O, we need to use the molar mass of the compound, which is the sum of the molar masses of each element in the formula.

The molar mass of Ba is 137.33 g/mol.
The molar mass of O is 16.00 g/mol.
The molar mass of H is 1.01 g/mol.

For Ba(OH)2·8H2O, we have:
(1 Ba x 137.33 g/mol) + (2 O x 16.00 g/mol) + (2 H x 1.01 g/mol) + (16 H x 2.02 g/mol) = 315.55 g/mol.

Now, we can calculate the moles of Ba(OH)2·8H2O using the given mass and the molar mass:

Moles = Mass / Molar Mass = 26.4 g / 315.55 g/mol = 0.0837 mol.

Since each Ba(OH)2 formula unit releases 2 hydroxide ions (OH-), the number of moles of OH- ions released will be twice the number of moles of Ba(OH)2 (0.0837 mol x 2 = 0.1674 mol).

Therefore, when 26.4 g of Ba(OH)2·8H2O dissolves in water, it releases 0.1674 moles of OH- ions.