Answer:
548 g/mol
Explanation:
The freezing point depression of a solvent occurs when a nonvolatile solute is added to it. Because of the interactions between solute-solvent, it is more difficult to break the bonds, so the phase change will need more energy, and the freezing point will drop, which is called cryoscopy.
The drop in temperature can be calculated by:
ΔT = Kf*W*i
Where Kf is the cryoscopy constant of the solvent, W is the molality, and i is the van't Hoff factor, which indicates the fraction of the solute that dissolves.
The molality represents how much moles (n) of the solute is presented in each kg of the solvent (m2), thus
W = n/m2
The number of moles is the mass of the solute (m1) in g, divided by the molar mass (M1) of it:
W = m1/(M1*m2)
So, by the data:
0.2214 = 0.632/(M1*0.00521)
0.00115M1 = 0.632
M1 = 548 g/mol
Answer:
endothermic reaction
Explanation:
When Elsa from Frozen freezes things, it is an example of an endothermic chemical reaction.
An endothermic involves a reaction in which heat is absorbed from the surrounding. Hence the surrounding becomes colder at the end of the the change.
So, Elsa draws heat from the environment and this causes the environment to be colder and things that are in contact with her.
Answer : The vapor pressure of the dry oxygen gas is, 736.2 torr
Explanation : Given,
Volume of sample of oxygen = 500 mL
Vapor pressure of oxygen + water = 760 torr
Vapor pressure of water = 23.8 torr
Now we have to determine the vapor pressure of the dry oxygen gas.
Vapor pressure of the dry oxygen gas = Vapor pressure of (oxygen + water) - Vapor pressure of water
Vapor pressure of the dry oxygen gas = 760 torr - 23.8 torr
Vapor pressure of the dry oxygen gas = 736.2 torr
Thus, the vapor pressure of the dry oxygen gas is, 736.2 torr
Answer:
the volume of CHCI3 = 7.87 ml
the volume of CHBr3 = 12.13 ml
Explanation:
From the given information:
We all know that 1 g/cm^3 = 1 g/ml
The density of boron = 2.34 g/ml
The Volume of the liquid mixture = 20 ml
Recall that:
Density = mass/volume
Mass = Density × Volume
Mass = 2.34 g/ml × 20 ml
Mass = 46.8 g
Suppose the volume of CHCI3 be Y and the Volume of CHBr3 be 20 - Y
Then :
Y (1.492) + 20-Y(2.890) = 46.8
1.492Y + 57.8 - 2.890Y = 46.8
- 1.398 Y = -11
Y = -11/ - 1.398
Y = 7.87 ml
Therefore, the volume of CHCI3 7.87 ml
the volume of CHBr3 = 20 - Y
= 20 - 7.87
= 12.13 ml