Answer : The molal freezing point depression constant of X is 
Explanation :  Given,
Mass of urea (solute) = 5.90 g
Mass of X liquid (solvent) = 450.0 g
Molar mass of urea = 60 g/mole
Formula used :  

where,
 = change in freezing point
 = change in freezing point
 = freezing point of solution =
 = freezing point of solution = 
 = freezing point of liquid X=
 = freezing point of liquid X= 
i = Van't Hoff factor = 1  (for non-electrolyte)
 = molal freezing point depression constant of X = ?
 = molal freezing point depression constant of X = ?
m = molality
Now put all the given values in this formula, we get
![[0.4-(-0.5)]^oC=1\times k_f\times \frac{5.90g\times 1000}{60g/mol\times 450.0g}](https://tex.z-dn.net/?f=%5B0.4-%28-0.5%29%5D%5EoC%3D1%5Ctimes%20k_f%5Ctimes%20%5Cfrac%7B5.90g%5Ctimes%201000%7D%7B60g%2Fmol%5Ctimes%20450.0g%7D)

Therefore, the molal freezing point depression constant of X is 
 
        
             
        
        
        
For average speed, we divide the total distance covered by the total time taken. 
After doing that, you will see that Jane has the lowest average speed.
 
        
             
        
        
        
Answer:
Groups like the Halogens, which include Chlorine and Flourine, share similar properties both behaviorally and structurally. The Periodic Table is essentially a bunch of patterns and trends and the groups (like the one with Sodium and Potassium) were grouped together because of these similarities. 
Explanation:
https://en.wikipedia.org/wiki/Alkali_metal
 
        
             
        
        
        
Answer:Noble gases:
  are highly reactive.
  react only with other gases.
  do not appear in the periodic table.
  are not very reactive with other elements.
Explanation:Noble gases:
  are highly reactive.
  react only with other gases.
  do not appear in the periodic table.
  are not very reactive with other elements.