[Fliss247]

ANY HELP WOULD BE SERIOUSLY APPRECIATED?? HOW DO I WORK THIS OUT?!

A nuclear chemist makes a solution by dissolving 0.428 g of uranium(IV) sulfate in water in a 40.00 mL volumetric flask and making it up to the mark. Calculate the concentration of the solution in mol/L??  using the appropriate significant figures.
Mr uranium(IV) sulfate = 574.28

Please explain how to calculate this Thank you!!

[sjb]

ANY HELP WOULD BE SERIOUSLY APPRECIATED?? HOW DO I WORK THIS OUT?!

A nuclear chemist makes a solution by dissolving 0.428 g of uranium(IV) sulfate in water in a 40.00 mL volumetric flask and making it up to the mark. Calculate the concentration of the solution in mol/L??  using the appropriate significant figures.
Mr uranium(IV) sulfate = 574.28

Please explain how to calculate this Thank you!!

How many miles of uranium sulfate do you have? In what volume?

[Fliss247]

Um, not sure as that was all that was given to me...

[Hunter2]

1. How is the concentration defined. Hint check units.
2. If you know this  convert the given mass to it.  Hint moles and mass has a relationship
3. Finaly you have to get it combined with your given volume.

[Fliss247]

1. How is the concentration defined. Hint check units.
2. If you know this  convert the given mass to it.  Hint moles and mass has a relationship
3. Finaly you have to get it combined with your given volume.

1. mol/l concentration therefore need to convert the mass to this
2. 0.428 x 1mol/ molar mass? (430.15 - looked this up) = 9.95x10^-04 mols/L
3. Concentration = 9.95x10^-4 / 0.04 = 0.024875? But this said it was wrong

so then tried:

2. 0.428 x 2mol/ molar mass? ( 574.28 - given value) = 7.45x10^-4
3. Concentration = 7.45x10^-4 / 0.04 = 0.018624 which is also wrong

haha so i really dont know what im doing wrong :\

[Hunter2]

In this case you do nothing wrong the molar Mass of U(SO₄)₂ ist 430 g/mol, the one of U(SO₄)₂ x 8 H₂O is 574 g/mol.

I think something wong with the given molar mass.

[mjc123]

Your last answer looks correct to me. However, you were asked to "use the appropriate significant figures", and you have not; perhaps that's why it gets marked wrong.