A certain substance X melts at a temperature of −9.9°C . But if a 350g sample of X is prepared with 31.8g of urea NH22CO dissolved in it, the sample is found to have a melting point of −13.2°C instead.
a. Calculate the molal freezing point depression constant Kf of X . Round your answer to 2 significant digits.

the molal freezing point depression constant Kf of X  = 2.18 degree celsius

Explanation:

The step by step calculation using the relationship between the depression of freezing point and the molal concentration is as shown in the attachment.

the dependant variable is spilled water

the independent is the heat

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