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. 10.1g of KNO, (FM-101g/mol) are dissolved in 5000g point is in 500.0g of water

ID: 577269 • Letter: #

Question

. 10.1g of KNO, (FM-101g/mol) are dissolved in 5000g point is in 500.0g of water Oe 186) The freezing A. -0.37 B. 0.37 D. -0.74°C E. -1.49 6. For which of the following would you expect the solubility wo temperature. A. Alcohol B. Table salt C. Sugar D. Carbon dioxide E. Baking soda Open Ended To determine the molar mass of an unknown o camphor. First the pure camphor is melted to determine its freezing poins. Then the solution is created according to the data below. The graph shows the resulis of the experiment. organic solute is dissolved in 1. mcamphce 100g ke(camphor)-400C SOLVENT A. What is the freezing point of the pure solvent? B. What is the freezing point depression in the experiment? C. What is the molar mass of the solute? (Show calculations) Time

Explanation / Answer

KNO3 will give two ions in water by dissociation

10.1g = 10.1/101g/mol = 0.1 mol

KNO3 -----> K+(aq) + NO3-(aq)

0.1 mol 0.1 mol 0.1 mol

total moles of ions in solution = 0.2 mol

change in freezing point = kfm

m = molality = moles of solute / mass of solvent in kg = 0.2 mol / 0.500kg = 0.4 m

kf = depression in freezing constant = 1.86 oC/m

depression in freezing point = 1.86 oC/m x 0.4 m = 0.744 oC

new freezing point = 0-0.744 = 0.74 oC

Ans = (d)

6.

gases solubility decreases with increase in temperature,here only carbon dioxide is gas present here

ans(D)