Molality-Chemistry Problem

Find molality of solution of Na2CO3 which has molarity of 1(M) and density of 1.098 g/cm3.

I would be very grateful of a correct answer.
Thank you in advance !

molar mass of Na2CO3 = 23*2+12+3*16=106g
a solution of density1.098g/cm3 weighs 1098g/L

SO 1 liter of that solution 1M contains 1098-106=992g=0.992kg of water

molality number of moles/kg of solvent

So molality =1/0.992=1.008moles of Na2CO3/kg of water

You can use this formula:
Molality, m=1000M/(1000d - M.x)

here, m=molality, M= molarity, d= density, x=molar mass of solute.

So, putting all the values, you get-

m=1000 x 1/ (1000x1.098 - 1x106) = 1000/992 = 1.008

:)