Question

In: Chemistry

Cyclohexane has a freezing point of 6.50 ∘C and a Kf of 20.0 ∘C/m. What is...

Cyclohexane has a freezing point of 6.50 ∘C and a Kf of 20.0 ∘C/m. What is the freezing point of a solution made by dissolving 0.771 g of biphenyl (C12H10) in 25.0 g of cyclohexane?

Solutions

Expert Solution

Answer – We are given, Cyclohexane freezing point = 6.50C , Kf = 20.0oC/m

Mass of biphenyl = 0.771 g , mass of cyclohexane = 25.0 g

First we need to calculate the moles of biphenyl

Moles of biphenyl = 0.771 g / 154.211 g.mol-1

                              = 0.005 moles

So molality of biphenyl = 0.005 moles / 0.025 kg = 0.200 m

We know the formula for freezing point depression

ΔTf = Kf*m

       = 20.0oC/m * 0.200 m

       = 4.00oC

We know the

Freezing point = Freezing point of pure solvent – ΔTf

                        = 6.50oC – 4.00oC

                        = 2.4oC


Related Solutions

The freezing point of water, H2O, is 0.000 °C at 1 atmosphere. Kf(water) = -1.86 °C/m...
The freezing point of water, H2O, is 0.000 °C at 1 atmosphere. Kf(water) = -1.86 °C/m In a laboratory experiment, students synthesized a new compound and found that when 11.70 grams of the compound were dissolved in 205.9 grams of water, the solution began to freeze at -0.587 °C. The compound was also found to be nonvolatile and a non-electrolyte.   What is the molecular weight they determined for this compound ?   ________ g/mol
calculate the freezing point of water (Kf= 1.86 C/m) for an ideal solution of sodium phosphate...
calculate the freezing point of water (Kf= 1.86 C/m) for an ideal solution of sodium phosphate which has a concetration of 3.25 m .
The Kf for acetic acid is 3.90 oC/m and its freezing point is 16.6 oC. Calculate the freezing point of a 1.25 M solution of benzoic acid
  The Kf for acetic acid is 3.90 oC/m and its freezing point is 16.6 oC. Calculate the freezing point of a 1.25 M solution of benzoic acid, C7H6O2 in acetic acid. The density of this solution is 1.067 g/mL. The density of pure acetic acid is 1.049 g/mL.
1. A) The freezing point of benzene, C6H6, is 5.500 °C at 1 atmosphere. Kf(benzene) =...
1. A) The freezing point of benzene, C6H6, is 5.500 °C at 1 atmosphere. Kf(benzene) = 5.12 °C/m In a laboratory experiment, students synthesized a new compound and found that when 11.43 grams of the compound were dissolved in 267.0 grams of benzene, the solution began to freeze at 4.740 °C. The compound was also found to be nonvolatile and a non-electrolyte. What is the molecular weight they determined for this compound? ____g/mol B) The boiling point of benzene, C6H6,...
The Kf for acetic acid is 3.90 oC/m and its freezing point is 16.6 oC. Calculate...
The Kf for acetic acid is 3.90 oC/m and its freezing point is 16.6 oC. Calculate the freezing point of a 1.25 M solution of benzoic acid, C7H6O2 in acetic acid. The density of this solution is 1.067 g/mL. The density of pure acetic acid is 1.049 g/mL.
The freezing point of benzene is 5.5°C. What is the freezing point of a solution of...
The freezing point of benzene is 5.5°C. What is the freezing point of a solution of 2.80 g of naphthalene (C10H8) in 355 g of benzene (Kf of benzene = 4.90°C/m)? Please answer in how many degrees of Celcius
Camphor has a melting point of 178.4℃ and a Kf of 37.7℃/m. If 0.550 g of an unknown nonelectrolyte lowered the freezing point of 35.0 g of camphor by 2.00℃
  A) Camphor has a melting point of 178.4℃ and a Kf of 37.7℃/m. If 0.550 g of an unknown nonelectrolyte lowered the freezing point of 35.0 g of camphor by 2.00℃, what was the molar mass of the unknown? B) When 1.00 g of hemoglobin is dissolved in enough water to form 100mL of solution, the osmotic pressure at 20℃ is 3.62x10-3 atm. What is the molar mass of the protein, hemoglobin?
What are the boiling point and freezing point of a 1.47 m solution of naphthalene in...
What are the boiling point and freezing point of a 1.47 m solution of naphthalene in benzene? (The boiling point and freezing point of benzene are 80.1°C and 5.5°C respectively. The boiling point elevation constant for benzene is 2.53°C/m, and the freezing point depression constant for benzene is 5.12°C/m.) Boiling point = °C Freezing point = °C
The boiling point of an aqueous solution is 102.34 °C. What is the freezing point?
The boiling point of an aqueous solution is 102.34 °C. What is the freezing point?
It takes 6.86 kg of ethylene glycol (antifreeze) to decrease the freezing point of 6.50 kg...
It takes 6.86 kg of ethylene glycol (antifreeze) to decrease the freezing point of 6.50 kg of water to -25.0ºF (-31.7ºC). How much lithium carbonate (Li2CO3) would it take to decrease the freezing point of 7.10 kg of water to -25.0ºF? (Assuming all the salt will dissolve in that amount of water.) 1) 5.68 kg 2) 8.95 kg 3) 4.48 kg 4) 2.98 kg 5) 2.35 kg
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT