Question

As you increase elevation the atmospheric pressure decreases, which means the boiling point of water also decreases. In Denver, the Mile High City, the boiling point of water is 95.0 degree C. a. How many grams of your assigned salt (using the van't Hoff factor you calculated in lab) would need to be added to 1.0 gallon (3.8 kg) of water to raise the temperature to 100.0 degree C, the boiling point of water at sea level. b. In the USA, a volume (cup) is used more commonly in cooking than a weight (grams). Convert the grams of salt you calculated into cups (1 cup = 273 g). c. Ignoring the potential toxicity of your assigned salt, is the amount of salt needed to increase the boiling point of the water 5 degree C reasonable?

Answer 1

a) The grams of the salt needed to be added is 1084.3 g

b) 4 cups

c) See the explanation.

Step-by-step explanation:

a) If the salt is NaCl, and the temperature rise from 95 to 100°C is equal to:

dT = 100 - 95 = 5°C

dT = i*Kb*m = 5 = 2 * 0.512/58.44 * 3.8

m = 1084. 3 g of salt needed

b) If 1 cup = 273 g, thus:

m = 1084.3/273 = 3.9 cups = 4 cups

c) Taking into account the amount of salt needed to raise the temperature by 5 ° C, the amount of salt that was calculated is reasonable

Answer 2

Check the explanation

Step-by-step explanation:

colligative property

a. let the salt in question is NaCl

to raise temperature of water from 95 to 100 oC

dTb = 100-95 = 5 oC

use,

dTb = iKbm = 5 oC

= 2 x 0.512 x grams NaCl/58.44 x 3.8

grams of NaCl salt needed = 1084.33 g

b. with,

1 cup = 273 g

thus,

amount of salt NaCl = 1084.33 g/273 = 3.97 cups (or 4 cups)

c. Yes, to raise the temperature of water by 5 oC the amount of salt needed for 3.8 kg water is reasonable.