<span>Tf is the freezing point of the solution(the solvent plus solute).
T*f is the freezing point of the pure solvent(without solute)
i is the van't Hoff factor.It is approximately the number of particles in solution that are made for each particle of the solute that is placed into solution.Therefore, for nonelectrolytes, i = 1.
Kf is the freezing point depression constant.For water, Kf = 1.86 Degree C/m, or 1.86 Degree C.kg/mol.
Tf is -1.58 Degree C</span>
<span>
Phenobarbital is derivative of
Barbituric Acid and Barbituric Acid is derivative of
Urea. (structures shown in Fig below)
Urea has H</span>₂N- group attached to Carbonyl Group (C=O), and such class of comounds conataining H₂N-C=O bond are called as Amides.
Result: So, <span>Phenobarbital belongs to
Amides.</span>
There should be 4.5 moles
Answer:
A. Coal
Explanation:
= water displaced by rock
Water displaced by rock = volume of water after rock is dropped into the cylinder - volume of water before the rock was dropped into the water
Water displaced by the rock = 180 ml - 150 ml = 30 ml

Density of rock:
40 grams => 30 ml
x grams => 1 ml
Cross multiply
1*40 = 30*x
40 = 30x
40/30 = 30x/30
1.3 = x
Density of rock = 1.3 g per 1 ml
Recall: 1 ml = 1 cm³
Therefore,
Density of the rock = 1.3 g/cm³
1.3 g/cm³ falls within the range of 1.1 - 1.4 g/cm³
Therefore, the rock is identified as Coal.