When 0.863 mol acetone is dissolved in 500 g benzene, the freezing point of benzene drops 8.84°c. what is the molal freezing point depression constant (kf) for benzene?

Explanation:

1) Data:

a) Solute: acetone

b) Solvent: benzene

c) n (solute) = 0.863 mol

d) mass of solvent = 500 g = 0.500 Kg

e) ΔTf = 8.84 °C

f) Kf = ?

2) Formulae:

3) Solution:

a) m = 0.863 mol / 0.500 kg = 1.726 m

b) Kf = ΔTf / m = 8.84°C / 1.726 m  = 5.12 °C/m ← answer

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.