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(2pt) Based on the solubility curve, which is more soluble in water at 50 o C, N

ID: 481537 • Letter: #

Question

(2pt) Based on the solubility curve, which is more soluble in water at 50oC, NaNO3, NH4Cl, KClO3, or NaCl? Explain your answer.

(2pt) Based on the solubility curve, how many grams of KCl will dissolve in 100 grams of 80°C Water? Explain your answer.

(3pt) A saturated solution of KNO3 in 400 grams of water at 50°C is cooled to 10°C. How much KNO3 will come out of the solution as crystals? Show your calculation.

(3pt) A student used 2.498g of a mixture of copper sulfate pentahydrate and salicylic acid in the performance of this experiment. The student recovered 1.184g of salicylic acid and 1.147g of copper sulfate pentahydrate. What is the mass % of recovered copper(II) sulfate pentahydrate? What is the mass % of recovered salicylic acid? What is the mass % of original sample not recovered? Show your calculation

150 400 130 120 110 a 100 0 10 20 30 40 50 60 70 80 90 100 Temperature (c)

Explanation / Answer

solubility of KNO3 : at 20 deg.c = 31.6 gmper 100 gm of water

at 50 deg.c = 80 gm per 100 gm of water

mass % of KNO3 in water at 80 deg,c = 80/(100+80) = 80/180 =0.444 and mass % of water = 1-0.444 =0.556

mass of KNO3 in 400 gm at 80 deg.c = 400*0.444=177.6 gm

mass of KNO3 at 20 deg,.c = 31.6 gm per 100 gm water

water present in 400 gm = 400*0.556 =222 gm

mass of saturated KNO3 at 20 deg.c = 31.6*222/100 =70 gm

mass of KNO3 that comes out = 177.6-70 = 107.6 gm

2.

mass of copper sulfate and salicylcic acid = 2.498 gm

mass of salicyclic acid =1.184 gm , mass % of copper sulfate recoverd = 100*(1.147/2.498)=45.92%

mass % of salicyclic acid = 100*1.184/ 2.498 =47.39

Mass % of mixture not recovered = 100-45.92-47.39 =6.71%