Question #d6c37

1 Answer
Aug 5, 2015


To determine the molarity of your solution, all you really need to do is figure out how many moles of urea you get in 6 grams of the substance.

Once you know how many moles you have, you can divide this number by the volume of the solution In liters to determine molarity.

So, urea has a molar mass of 60.055 g/mol, which means that you get 1 mole for every 60.055 g.

The number of moles you get will be equal to

#6color(red)(cancel(color(black)("g"))) * "1 mole"/(60.055color(red)(cancel(color(black)("g")))) = "0.0999 moles"#

You can assume the density of the solution to be equal to that of water, #"1 g/mL"#, which means that you get a volume of

#100color(red)(cancel(color(black)("g"))) * "1 mL"/(1color(red)(cancel(color(black)("g")))) = "100 mL"#

The molarity of the solution will thus be

#C = n/V = "0.0999 moles"/(100 * 10^(-3)"L") = "0.999 M"#

Rounded to one sig fig, the answer will be

#C = color(green)("1 M")#