A 3g of sample of Na2CO3.10H2O is heated to a constant mass. How much anhydrous salt remains?

Dear Student,


Washing soda on heating converted to anhydrous Sodium carbonate.



Na₂CO₃:  2(23.0) + 12.0 + 3(16.0) = 106.0 g
H₂O: 18.0 g
Na₂CO₃• 10H₂O (total): (106+10*18) = 286 g
286 g of Na₂CO₃• 10H₂O produces = 106 g of Na₂CO₃
3 g of  Na₂CO₃• 10H₂O produces =  (106*3)/286 g of Na₂CO_{3
                                                                 =} 1.11  g of Na₂CO₃
Mass of anhydrous Salt = 1.11 g

Regards