36. A volume of 10.00 nitrate has a mass of 13.6 g. When the solvent was evapora

Question

36. A volume of 10.00 nitrate has a mass of 13.6 g. When the solvent was evaporated, the residual solid had a mass of 4.54 g. Calculate the concentration of thesolution in %(m/m) %(m/v), and Molarity. mL of an aqueous solution of sodium Extra Credit, Essay Question (6 points). A town in upstate New York sometimes applies CaCl2 to help to prevent freezing and ice accumulation on bridges and overpasses. They do this in spite of the fact that CaClz is more expensive than N Explain why the town's Road Crew might opt to apply calcium chloride to the road surfaces rather than sodium chloride. Your answer should be based on the chemical properties of solutions and should include specific references to the applicable equations. (Continue on the back if more room is needed.)

Explanation / Answer

Molecular formula of sodium nitrate is NaNO3

and molar mass of sodium nitrate is

= Na x 1 + N x 1+ O x 3

= 23 x 1 + 14 x 1 + 16 x 3

= 23 + 14 + 48

= 85

Mass of solid residue remaining = 4.54 g

i.e. mass of sodium nitrate remaining = 4.54 g

so moles of sodium nitrate remaining = 4.54/85 = 0.053 moles

weight of water evoprated = 13.6 - 4.54 = 9.06 g

ans) concentration of solution is = (4.54/13.6)*100 = 33.38 % (m/m)

ans) concentration of solution is = (4.54/10)*100 = 45.4 % g/ml (m/v)

moles of water evoprated = 9.06/18 = 0.50 moles

where moleculer mass of water is 18

So total number of moles in solution = 0.053 + 0.5 = 0.553 moles

Total volume of solution = 10 ml = 10/1000 liter = 0.01 liter

molarity of solution is moles present in liter of solution

ans) so molarity of the solution is = 0.053/0.01 = 5.3 mol/liter

Sodium chloride is solid where as calcium chloride is liquid

working temperature for sodium chloride is 12F or warmer whereas working temperature for calcium chloride is as low as -13F

sodium chloride takes much time to melt the ice compared to calcium chloride which works instantly

Due to these reasons though calcium chloride is expensive compared to sodium chloride road crew might apply calcium chloride than sodium chloride

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