Question

In an ethylene glycol-water solution, there are 20.0 g ethylene glycol for every 80.0 g water. This solution is used for filling a 450.0 gallon reservoir. Suppose the density of this mixture solution is ρ= 1.0529 g/ml. (a) What is the molarity of this solution? (b) If you need to fill the 450.0 gallon tank in 170.0 s, what is the volumetric flow rate of the solution into the tank? (c) How many moles of ethylene glycol are in the tank when it is filled?

Answer 1

100 g of solution 20 - g Ethylene glycol - solute 80 - g water - solvent density of solution(S) = 1.0529 g/ml = 1.0529 kg/litre Molecular weight of Ethylene glycol = 62 g/mol Molecular weight of water = 18 g/mol a) Molarity (M) = Number of moles of solute/Volume of solution in litres Density = Mass/Volume Moles = Given Mass/Molecular weight Volume = Mass/ Density Volume of 100g solution (V) = 100 g/1.0529 g/ml = 94.97578 ml = 0.09498 litres Molarity (M) = mass of Ethylene glycol/Molecular weight/volume of solution in litres = 20g/62 g/mol/0.09498 litres = 3.3964 mol/l \r\n b) Volume of tank = 450 gallon Time to fill = 170 S Volumetric flow rate of solution = volume of tank/time to fill = 450 gallon/170 S = 2.647 gallon/S 1 gallon (VS) = 3.78541 litres = 2.847 times 3.78541 litres/S = 10.02 litres/sec c) Volume of Tank = 450 gallon = 450 times 3.78541 litres = 1703.4345 litres Mass of solution = Density of solution times Volume of Tank = 1.0529 kg/litres times 1703.4345 litres = 1793.546 kg Since for every 100 g of solution 20 g is Ethylene glycol means 20% of total weight of 100 g is Ethylene glycol in solution weight of ethylene glycol in 1793.546 kg solution = 20/100 times 1793.546 = 358.7092 kg