When substances such as sugar and table salt are dissolved in water, the freezing points of the new solutions are lower than the freezing point of water. Also, the more material dissolved, the lower the freezing point. The boiling points of these solutions, however, are higher than that of water.
Which of the followingsolutions would have the highest boiling point?
1) 5 liters of water
2) 5 grams of salt dissolved in 4 liters of water
3) 10 grams of salt dissolved in 3 liters of water
4) 15 grams of salt dissolved in 2 liters of water
5) 20 grams of salt dissolved in 1 liter of water
i really have no idea
See above.
Isn't change in boiling point
delta T = i*Kb*m
i = 2 for NaCl.
Kb stays a constant.
molality = m = moles/kg solvent.
It appears to me that the highest m will have the highest delta T. So which is the highest m.
To determine which solution would have the highest boiling point, we need to understand how the boiling point elevation works when solutes are dissolved in water.
The boiling point elevation occurs because the solute particles disrupt the formation of the water vapor molecules, making it more difficult for the liquid to change to a gas. The more solute particles there are in the solution, the higher the boiling point will be.
In this case, we can calculate the number of solute particles for each solution using the amount of salt dissolved in the given volume of water. We can then compare the solutions based on the number of solute particles.
1) 5 liters of water: This solution contains no solute particles.
2) 5 grams of salt dissolved in 4 liters of water: To determine the number of solute particles, we need to convert grams to moles. The molar mass of salt (NaCl) is approximately 58.44 g/mol. Hence, we have:
- Salt: 5 g / 58.44 g/mol ≈ 0.086 mol
- Water: 4 L * 55.56 mol/L ≈ 222.24 mol (assuming water density of 1 g/mL)
- Total: 0.086 mol + 222.24 mol ≈ 222.33 mol of solute particles
3) 10 grams of salt dissolved in 3 liters of water:
- Salt: 10 g / 58.44 g/mol ≈ 0.171 mol
- Water: 3 L * 55.56 mol/L ≈ 166.68 mol
- Total: 0.171 mol + 166.68 mol ≈ 166.85 mol of solute particles
4) 15 grams of salt dissolved in 2 liters of water:
- Salt: 15 g / 58.44 g/mol ≈ 0.257 mol
- Water: 2 L * 55.56 mol/L ≈ 111.12 mol
- Total: 0.257 mol + 111.12 mol ≈ 111.38 mol of solute particles
5) 20 grams of salt dissolved in 1 liter of water:
- Salt: 20 g / 58.44 g/mol ≈ 0.343 mol
- Water: 1 L * 55.56 mol/L ≈ 55.56 mol
- Total: 0.343 mol + 55.56 mol ≈ 55.90 mol of solute particles
Based on the calculations, the solution with the highest boiling point would be:
2) 5 grams of salt dissolved in 4 liters of water, which has approximately 222.33 mol of solute particles.
Hence, solution 2 would have the highest boiling point among the given options.