Imagine two solutions with the same concentration and the same boiling point.?
Imagine two solutions with the same concentration and the same boiling point, but one has ethanol as the solvent and the other has carbon tetrachloride as the solvent. Determine that concentration and boiling point.
ethanol: 78.4 Celsius 1.22 c/m
carbon tetrachloride: 76.8 Celsius 5.03 c/m
works
If both solutions have the same concentration and boiling point, it means that they contain the same amount of solute per unit of solvent.
However, since the solvents are different (ethanol and carbon tetrachloride), their boiling points and colligative properties will also differ.
For the ethanol solution:
- Boiling point: 78.4 degrees Celsius
- Colligative property (elevation in boiling point): 1.22 degrees Celsius per molal (c/m)
For the carbon tetrachloride solution:
- Boiling point: 76.8 degrees Celsius
- Colligative property (elevation in boiling point): 5.03 degrees Celsius per molal (c/m)
To determine the concentration and boiling point of two solutions with the same concentration and the same boiling point, but different solvents (ethanol and carbon tetrachloride), I will explain the steps you can follow:
1. Start by understanding what "concentration" means in this context. Concentration refers to the amount of solute (the substance being dissolved) in a given amount of solvent (the substance doing the dissolving). It is usually expressed as moles of solute per liter of solution.
2. Next, note that the boiling point of a solution depends on the concentration of the solute present. When a solute is added to a solvent, it raises the boiling point of the solution compared to the pure solvent.
3. In this case, since we have two solutions with the same concentration and the same boiling point, it means that the amount of solute dissolved in both ethanol and carbon tetrachloride is the same.
4. The boiling points provided are 78.4 degrees Celsius for ethanol and 76.8 degrees Celsius for carbon tetrachloride.
5. In addition to the boiling points, we are also given the colligative properties of each solvent. Colligative properties are properties that depend on the concentration of the solute particles, rather than the identity of the solute itself. One such colligative property is the boiling point elevation, represented by "c/m" in this case.
6. The values provided show that ethanol has a boiling point elevation of 1.22 c/m, whereas carbon tetrachloride has a boiling point elevation of 5.03 c/m. This means that for every mole of solute dissolved in ethanol, the boiling point of the solution will increase by 1.22 degrees Celsius. Similarly, for every mole of solute dissolved in carbon tetrachloride, the boiling point of the solution will increase by 5.03 degrees Celsius.
7. Since both solutions have the same concentration and boiling point, and we know the boiling point elevation for each solvent, we can conclude that the concentration of the solute in both solutions is constant. However, the amount of solute needed to reach the same concentration will be different for each solvent due to the different boiling point elevations.
Therefore, to determine the exact concentration of the solute in each solution, additional information regarding the amount of solute used or the total solution volume would be required.
The boiling points are 1.6 degrees apart; i.e., 78.4-76.8 = 1.6 so the CCl4 must increase 1.6 more than the ethanol.If you want the boiling point to be the same, that means you want
[1.22*m + 1.6] = 5.03*m
and solve for m = about 0.42. We can check that out from dT = Kb*m
dTethanol = 1.22*0.42 = 0.51 so b.p. = 78.4 + 0.51 = 78.9
dTCCl4 = 5.03*0.42 = 2.1 so b.p. = 76.8 + 2.1 = 78.9 and voila, the b.p. are the same. The concns are, or course, 0.42 m.