Question

The molal freezing point depression constant K,-2.44 °C.kg mol for a certain X, the solution freezes at -9.6 °C. calculate the freezing point of pure X Round your answer to 2 significant digits. 

Answer 1

Answer 2

A certain substance 

X

 has a normal freezing point of 

−6.5°C

 and a molal freezing point depression constant 

=Kf·7.48°C·kgmol−1

. A solution is prepared by dissolving some urea 

NH22CO

 in 

850.g

 of 

X

. This solution freezes at 

−12.9°C

. Calculate the mass of urea that was dissolved.

Round your answer to 

2

 significant digits.