1.

Calculate the mass of urea (NH2CONH2) required in making 2.5 kg of 0.25 molal aqueous solution.

Answer»

0.25 molal aqueous solution of urea means that 0.25 mole of urea are present in 1 kg of water  
Moles of urea = 0.25mole 
Mass of solvent (water) = 1 kg = 1000 g 
Molar mass of urea (NH2CONH2) = 60 g mol
1. 0.25moleofurea=0.25mol×60gmol1=15g 
Total mass of solution=1000+15g=1015g=1.015kg

 Thus; 1.015 kg of solution contain urea = 15g×2.5kg of solution will require urea

\(\frac{15g}{1.015kg}\times2.5kg=37g\)



Discussion

No Comment Found

Related InterviewSolutions