Answer:
First you'll need to divide the mass of K2Cr2O7 by its molar mass and volume which should be easy but I'll do some of it to help you out
Explanation:
[tex]K_{2}Cr_{2}O_{7}[/tex]
[tex]2K = 39.098 = 2(39.098) = 78.196[/tex]
[tex]2Cr = 51.996 = 2(51.996) = 103.992[/tex]
and
[tex]7O = 15.999 = 7(15.999) = 111.993[/tex]
[tex]78.196 + 103.992 + 111.993 = 294.181[/tex]
so that's the mass of K2Cr2O7 and then you divide it by the molar mass and volume.
Hopefully you can do that on your own! Hope I helped a bit atleast and I have a good feeling about 0.438 but I don't want you to just guess
