To a solution containing 7.2 g of copper sulfate (2) was added a solution containing 2.34 g

To a solution containing 7.2 g of copper sulfate (2) was added a solution containing 2.34 g of sodium sulfide. Determine the mass of precipitated sediment

The reaction equation for salt exchange is:
CuSO4 + Na2S = Na2SO4 + CuS, equimolar amounts of substances enter and are obtained.
The molar masses of CuSO4 and Na2S are 160 g / mol and 78 g / mol, respectively. This means that 7.2 of them entered into a reaction: 160 = 0.045 mol and 0.03 mol, you will have to count on a smaller number.
The CuS precipitate is also precipitated in an amount of 0.03 mol, weighing 0.03 * 96 = 2.88 g.