LIVE Course for free

Rated by 1 million+ students
Get app now
0 votes
68.1k views
in Solutions by (46.8k points)
closed by

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

1 Answer

+2 votes
by (47.9k points)
selected by
 
Best answer

0.25 molal aqueous solution means that 

Moles of urea = 0.25 mole 

Mass of solvent (water) = 1 kg = 1000 g 

Molar mass of urea = 14 + 2 + 12 + 16 + 14 + 2 = 6O g mol-1 

0.25 mole of urea = 60 x 0.25 mole = 15 g

Total mass of the solution = 1000 + 15 g = 1015 g = 1.015 g 

Thus, 1.015 kg of solution contain urea = 15 g 

2.5 kg of solution will require urea = \(\frac{15}{100}\) x 2.5 kg = 37g

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

...