hi. I need some help please :)

solution is prepared by dissolving ethanol P(density)=0.789 g/ml in enough water to produce half liter of sol. Solve for molarity.

Question

hi. I need some help please  :) 

solution is prepared by dissolving ethanol P(density)=0.789 g/ml in enough water to produce half liter of sol. Solve for molarity.

jfraser · Answer

you're missing the amount of ethanol added. this can't be solved without it

ulahlynn · Answer

is it incorrect if the density is given?

jfraser · Answer

the density is necessary if you're given a VOLUME of ethanol added, but you need to know how much. Density by itself isn't enough.

ulahlynn · Answer

ohh... thanks for clearing this up :) .

ulahlynn · Answer

but can i ask just one more :D

solve how many grams of acetone is dissolved in enough water to produce 1.25L of solution if the molarity is 0.3 M.

jfraser · Answer

molarity is $$M = \frac{mol solute}{L solution}$$and you're given the molarity and the total volume. Solve for the moles of acetone, then use the molar mass of acetone to find grams

ulahlynn · Answer

ok.. thank you soo much!.

jfraser · Answer

yw