Question #5b4e9
1 Answer
Explanation:
A solution's molality tells you how many moles of solute you get for every
In this regard, a
Now, in order to find the solution's percent concentration by mass,
To convert the number of moles of glucose to grams, use the compound's molar mass
#1 color(red)(cancel(color(black)("mole glucose"))) * "180.156 g"/(1color(red)(cancel(color(black)("mole glucose")))) = "180.156 g"#
So, you know that you have
#1 color(red)(cancel(color(black)("kg"))) * (10^3color(white)(.)"g")/(1color(red)(cancel(color(black)("kg")))) = "1000 g"#
of water, which means that the total mass of the solution will be
#m_"total" = "180.156 g" + "1000 g" = "1180.156 g"#
You can now use the known composition of the solution to determine how many grams of glucose would be present in
#100 color(red)(cancel(color(black)("g solution"))) * "180.156 g glucose"/(1180.156color(red)(cancel(color(black)("g solution")))) = "15.3 g glucose"#
Since this is how many grams of glucose you have for every
#color(darkgreen)(ul(color(black)("% m/m" = 15.3%)))#
I'll leave the answer rounded to three sig figs, but keep in mind that you only have one significant figure for the molality of the solution and for the mass of water.