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in 115 g of water is °C. The by dissolving 11.3 g of urea (MM-60.06 gmol is a mo

ID: 1076868 • Letter: I

Question

in 115 g of water is °C. The by dissolving 11.3 g of urea (MM-60.06 gmol is a molal freezing point depression constant for water is 1.86 c/m. (Assume 10096 ionization of KBn) O 3.01 O-3.01 O-0.350 O 0.00 QUESTION 15 How many liters of ethylene glycol (CH2(0HCH21OH): MM-62.07 g/mo) would you add to a car radiator containing 7.30 L of water if the temperature in DC is expected to reach -15.0 C? The density of ethylene glycol is 1.11 g/mL Report your answer with the correct number of significant figures; DO NOT include units QUESTION 16 ) of table salt, NC, to 5.00L of water to cook her family pasta. At what temperature will her water boil after the addition of the salt? The molal boiling point depression constant for water is 0.51 °C/m. (Assume 100% ionization of NaCl) O 100.00 °c 99.69 O 100.31 °C O 100.16 O 031 C Dr. H adds 90.0 g (3

Explanation / Answer

Ans : -3.01oC

The depression in freezing point is given as = kf. m

where kf = freezing point constant = 1.86oC / m

m is molality

no. of moles of urea = given mass / molar mass

= 11.3 / 60.06

= 0.189 mol

molality = no. of moles of urea / mass of water in kg

= 0.189 / 0.115

= 1.64 m

Depression = 1.86 x 1.64

= 3.01oC

So the freezing point of the solution = 0 - 3.01

= -3.01oC