Incorrect dilution values per text implications.

[atmega-ist]

Homework Statement

Volumes of 1, 5, 10 and 15mL .0024M K2CrO4 are added to separate flasks and then filled with enough .25M NaNO3 to make 100mL of solution each. I'm asked to calculate the [CrO4^2-] per flask. I assume that all of the K2CrO4 will dissociate and, since there is only 1mol CrO4^2- per mole of K2CrO4, the [CrO4^2-] = [K2CrO4].

Homework Equations

M1V1 = M2V2 ==> M2 = M1V1/V2

The Attempt at a Solution

My calculations gave me the following values for each flask.

Flask with 1mL K2CrO4: [CrO4^2-] = 2.4x10^-5M

Flask with 5mL K2CrO4: [CrO4^2-] = 1.2x10^-4M

Flask with 10mL K2CrO4: [CrO4^2-] = 2.4x10^-4M

Flask with 15mL K2CrO4: [CrO4^2-] = 3.6x10^-4M

My concern, though, is that the text asks me to graph these values against the corresponding volume of K2CrO4 for each flask but the values of the x-axis ([CrO4^2-]) on the suppplied graph range from 0 to 3.6x10^4 are marked in increments of .2x10^4... Would it seem that this is supposed to be ten-to-the-negative fourths or have I completely missed something?

It seems to me that any concentration of 2000M is a bit steep. Also - why would a decimal be used if it were intended to be expressed in thousands rather than thousandths?

All of my data would fit on the table if it were a typo but with the concentration of the 1mL flask being to the negative 5th I thought I'd see if anyone could help me find the error.

Thank you

 

[Borek]

Must be a typo. Your approach is correct.

In general concentrations higher than 10M are very rare, highest concentration I can think of is that of pure water - 55.5 M. Concentrated acids can get up to about 17 or 18M.