Calculate the molality of a solution containing 20.7 g of K2CO3 dissolved in 500 mL of the solution (assuming density of solution = 1 g/ml)  

Calculate the molality of a solution containing 20.7 g of K2CO3 dissolved in 500 mL of the solution (assuming density of solution = 1 g/ml)  

Answer:

Given Values

WB = 20.7 gm

MB = K2CO3 = 2(39)+12+3(16) = 138

Dsol = 1 gm/ml

Vsol = 500 ml

∴  Wsol = Dsol × Vsol = 500 gm

Calculate

molality = \( \frac{W_{B} \times 1000}{M_{B}~\left ( W_{sol}-W_{B} \right )} \)

molality = \( \frac{20.7 \times 1000}{138~\left ( 500-20.7 \right )} \) 

molality = 0.313 mol/kg

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