A mass of 4.133g of sodium carbonate crystals Na2CO3.XH2O (s) was heated gently and 3.533g of anhydrous compound remained. Calculate the value of X.

1

Explanation:

From the question, the following were obtained:

Mass of hydrated salt(Na2CO3.XH2O) = 4.133g

Mass of anhydrous salt(Na2CO3) = 3.533g

Mass of water = 4.133 — 3.533 = 0.6g

Next, we convert these grams to moles

MM of Na2CO3 = (23 x 2)+12+(16x3) = 46+12+48) = 106g/mol

Number of mole = Mass /Molar Mass

Number of mole of Na2CO3 = 3.533/106 = 0.033mol

MM of water (H2O) = (2x1) +16 = 2+16 =18g/mol

Number of mole of H2O = 0.6/18 = 0.033mol

Next, we find the ratio of the mole of anhydrous salt to the water. This done below:

Mole of anhydrous : mole of water = 0.033 : 0.033 = 1 : 1

The number of mole of water attached to the salt is 1

The formula of the hydrated salt is CuSO4.H2O