How many grams of manganese (IV) oxide are needed to make a 5.6 liters of a 2.1 M solution?

The number of moles of solute required to make a solution of
molarity 1 is 1 mole per liter. To make a solution of manganese dioxide with a molarity of 2.1 M
will require 2.1 moles of the solute per liter of the solution.

The
molar mass of manganese (IV) oxide or manganese dioxide is 86.9368 g / mole. 2.1 mole of
manganese dioxide weighs 2.1*86.9368 = 182.56 g.

As we need to make
5.6 liters of the 2.1 M solution the amount of manganese dioxide required is
1022.37

Therefore we get the mass of manganese dioxide required to
make 5.6 liters of a 2.1 M solution as 1022.37 g