the degree or intensity of heat present in a substance or object, especially as expressed according to a comparative scale and shown by a thermometer or perceived by touch. So I would have to go with A.
Answer:
1.62
Explanation:
From the given information:
number of moles of benzamide ![=\dfrac{70.4 \ g}{121.14 \ g/mol}](https://tex.z-dn.net/?f=%3D%5Cdfrac%7B70.4%20%5C%20g%7D%7B121.14%20%5C%20g%2Fmol%7D)
= 0.58 mole
The molality = ![\dfrac{mass \ of \ solute (i.e. \ benzamide )}{mass \ of \ solvent }](https://tex.z-dn.net/?f=%5Cdfrac%7Bmass%20%5C%20of%20%5C%20solute%20%28i.e.%20%5C%20benzamide%20%29%7D%7Bmass%20%5C%20of%20%5C%20solvent%20%20%7D)
![= \dfrac{0.58 }{0.85 }](https://tex.z-dn.net/?f=%3D%20%5Cdfrac%7B0.58%20%7D%7B0.85%20%7D)
= 0.6837
Using the formula:
![\mathbf {dT = l \times k_f \times m}](https://tex.z-dn.net/?f=%5Cmathbf%20%7BdT%20%20%3D%20l%20%20%20%5Ctimes%20%20k_f%20%20%5Ctimes%20m%7D)
where;
dT = freezing point = 27
l = Van't Hoff factor = 1
kf = freezing constant of the solvent
∴
2.7 °C = 1 × kf × 0.6837 m
kf = 2.7 °C/ 0.6837m
kf = 3.949 °C/m
number of moles of NH4Cl = ![\dfrac{70.4 \ g}{53.491 \ g /mol}](https://tex.z-dn.net/?f=%5Cdfrac%7B70.4%20%5C%20g%7D%7B53.491%20%5C%20%20g%20%2Fmol%7D)
= 1.316 mol
The molality = ![\dfrac{1.316 \ mol}{0.85 \ kg}](https://tex.z-dn.net/?f=%5Cdfrac%7B1.316%20%5C%20mol%7D%7B0.85%20%5C%20kg%7D)
= 1.5484
Thus;
the above kf value is used in determining the Van't Hoff factor for NH4Cl
i.e.
9.9 = l × 3.949 × 1.5484 m
![l = \dfrac{9.9}{3.949 \times 1.5484 \ m}](https://tex.z-dn.net/?f=l%20%3D%20%5Cdfrac%7B9.9%7D%7B3.949%20%5Ctimes%201.5484%20%5C%20m%7D)
l = 1.62
Explanation:
The lack of a control group