Freezing & Boiling Point

A solution of saltwater raised the boiling point of water from 100 degrees Celsius to 102.5 degrees Celsius. What is the molality of the solution? [Kb of water is 0.51 C/m]

• 9.4 m

• 7.3 m

• 5.9 m

• 2.5 m

Suppose Jasim had solute dissolved into diethyl ether which has caused the freezing point of diethyl ether to decrease by 4.75 degrees Celsius. What is the concentration, in molality, of the solution? [Kf of diethyl ether is -1.79 C/m]

• 1.75 m

• 2.25 m

• 2.75 m

• 3.45 m

Ali dissolve 30.0 g of potassium iodide (KI) into 1750 g of water, what will be the change in the freezing point of his solution? [Kf of water is -1.86 C/m]

• 0.19 C

• -0.19 C

• 2.85 C

• -2.85 C

If you use 5.76 mol of sodium fluoride (NaF) and dissolve this into 3.62 kg of water, what will be the change in the boiling point of your solution? [Kb of water is 0.51 C/m]

• 0.81 C

• -0.81 C

• -1.78 C

• 1.78 C

Tags

NGSS.HS-PS3-1

If you use 3.68 mol of sucrose (C12H22O12) and dissolve this into 2.50 kg of water, what will be the change in the freezing point of your solution? [Kf of water is -1.86 C/m]

• -1.74 C

• 1.74 C

• -2.74 C

• 2.74 C