Question

Calculate the mass of K2CO3 which will have the same number of molecules as
contained in 12.3 g of MgSO4.7H2O.

Answer 1

▶ Solution :

Given :-

Mass of MgSO4▪7H2O = 12.3g

To Find :-

Mass of K2CO3 which will have the same number of molecules as contained in the given amount of MgSO4▪7H2O

Concept :-

✏ First we have to find out moles of each compound after that we can calculate number of molecules.

✏ Formula of no. of moles in terms of weight of ckmpound and molecular weight of compound is given by

$\boxed{\bf{\pink{mole=\dfrac{weight(w)}{Molecular\:weight(M_w)}}}}$

✴ Mw of K2CO3 = 138g/mol

✴ Mw of MgSO4▪7H2O = 246g/mol

Calculation :-

$\leadsto\bf\:Molecules\:of\:K_2CO_3=Molecules\:of\:MgSO_4\:7H_2O\\ \\ \leadsto\sf\:(\dfrac{w}{M_w})_{K_2CO_3}\times N_A=(\dfrac{w}{M_w})_{MgSO_4\:7H_2O}\\ \\ \leadsto\sf\:\dfrac{w}{138}=\dfrac{12.3}{246}\\ \\ \leadsto\sf\:w=\dfrac{12.3\times 138}{246}\\ \\ \leadsto\boxed{\bf{\purple{Weight\:of\:K_2CO_3=6.9g}}}$