Answer:
Boiling point depression is defined as
∆Tb=i x Kb x m
Where ∆Tb=(Tb)solution-(Tb)solvent,
i=Vant Hoff's factors=number of ions
Kb=boiling point constant
m= Molarity=(weight/molecular weight)(1000/weight of solvent).
Given (Tb)solution=103 °C, (Tb)solvent=100 °C,
i=3, Kb=0.512 °C/m, weight of sample=15.3 g, weight of solvent (water)=110 g.
Substitute all these values in above expression
∆Tb= i x Kb x m
(Tb) solution-(Tb) solvent= i x Kb x (weight/molecular weight)(1000/weight of solvent)
(103°C-100°C)=3 x 0.512 °C/m x (15.3g/molecular weight)(1000/110g).
Molecular weight=(213.643)/3=71.215 g/mol
Molar mass of sample =71.215 g/mol.
A 15.3 g sample of a compound known to contain 3 ion species is dissolved in...
The freezing point of water is 0.00°C at 1 atmosphere. A student dissolves 12.54 grams of chromium(II) acetate, Cr(CH3COO)2 (170.1 g/mol), in 158.2 grams of water. Use the table of boiling and freezing point constants to answer the questions below. Solvent Formula Kb (°C/m) Kf (°C/m) Water H2O 0.512 1.86 Ethanol CH3CH2OH 1.22 1.99 Chloroform CHCl3 3.67 Benzene C6H6 2.53 5.12 Diethyl ether CH3CH2OCH2CH3 2.02 The molality of the solution is m. The freezing point of the solution is °C....
The boiling point of water is 100.00 °C at 1 atmosphere. A student dissolves 12.31 grams of cobalt(II) acetate, Co(CH3COO)2 (177.0 g/mol), in 287.1 grams of water. Use the table of boiling and freezing point constants to answer the questions below. Solvent Formula Kb (°C/m) Kf (°C/m) Water H2O 0.512 1.86 Ethanol CH3CH2OH 1.22 1.99 Chloroform CHCl3 3.67 Benzene C6H6 2.53 5.12 Diethyl ether CH3CH2OCH2CH3 2.02 The molality of the solution is _____m. The boiling point of the solution is °____C....
0.230 g of a compound is dissolved in 10 g of cyclohexane. the solution freezes at 5.12 degrees celcius. calculate the molecular weight of the compound. the freezing point of pure benzene is 5.455 degrees Celsius and the kf = 5.065 degrees Celsius/ m
Quinine is a natural product extracted from the bark of the cinchona tree, which is native to South America. Quinine is used as an antimalarial agent. When 1.68 g of quinine is dissolved in 25.0 g of cyclohexane, the freezing point of the solution is lowered by 4.31∘ C. The freezing point and Kf constant for cyclohexane can be found here. Calculate the molar mass of quinine. Solvent Formula Kf valueNormal freezing Kb value Normal boiling point (°C) 0.00 5.49...
A 2.50 g sample of naphthalene, C10H8, was dissolved in 100 g of benzene. What is the freezing point of the solution? The freezing point of pure benzene is 5.45 degrees Celsius; Kf=5.07 degrees Celsius/m. The molar mass of C10H8 is 128.17 g/mol The answer is supposed to be 4.46 degrees Celsius. How did they get there?
The freezing point of water is 0.00°C at 1 atmosphere. How many grams of cobalt(II) bromide (218.7 g/mol), must be dissolved in 287.0 grams of water to reduce the freezing point by 0.350°C ? Refer to the table for the necessary boiling or freezing point constant. Solvent Formula Kb (°C/m) Kf (°C/m) Water H2O 0.512 1.86 Ethanol CH3CH2OH 1.22 1.99 Chloroform CHCl3 3.67 Benzene C6H6 2.53 5.12 Diethyl ether CH3CH2OCH2CH3 2.02
Lysozyme extracted from chicken egg white has a molar mass of 13,930 g/mol. Exactly 0.1 g of this protein is dissolved in 50 g of water at 298 K. Assuming that the protein is a nonelectrolyte, calculate the following: a. Vapor-pressure lowering (Pvap, H₂O = 23.76 mmHg at 298 K). b. Boiling-point elevation (Kb of H₂O=0.512 °C/m) c. Freezing-point depression (Kf of H₂O= 1.86 °C/m) d. Osmotic pressure
The freezing point of water is 0.00°C at 1 atmosphere. How many grams of nickel(II) sulfate (154.8 g/mol), must be dissolved in 210.0 grams of water to reduce the freezing point by 0.400°C ? Refer to the table for the necessary boiling or freezing point constant. Solvent Formula Kb (°C/m) Kf (°C/m) Water H2O 0.512 1.86 Ethanol CH3CH2OH 1.22 1.99 Chloroform CHCl3 3.67 Benzene C6H6 2.53 5.12 Diethyl ether CH3CH2OCH2CH3 2.02 g nickel(II) sulfate.
What is the freezing point and boiling point in Celsius of a solution 400 g of ethylene glycol (MW=62 g/mol) dissolved in 500 g of water? The molal freezing point depression constant for water is 1.86 C/m The molal boiling point elevation constant of water is 0.512 C/m Please explain steps
29) A solution is 0.0433 m LiF. What is the molarity of the solution if the density is 1.10 g/mL? A) 0.0441 M B) 0.0390 M C) 0.0476 M D) 0.0417 M E) 0.0519 M 30) Determine the freezing point depression of a solution that contains 30.7 g glycerin (C3H8O3, molar mass =92.09 g/mol) in 376 mL of water. Some possibly useful constants for water are Kf 1.86°C/m and Kb 0.512°C/m. A) 3.33°C B) 0.654°C C) 1.65°C D) 4.95°C E)...