# Chemistry again

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Chromium is ametal that is added to steel to improve its resitance to corrosion. Calculate both the number of miles in a sample of Cr containing 5.00 x 10^20 atms and the mass of the sample.

Ok this is how I worked it.

1 mole of Cr = 51.996g = 6.022 x 10^23 atoms

(whatever mass is) 6.022 x 10^23 atom/51.996g = 5.00 x 10^20

After I solved that, I ended up with the mass being 4.32g

Okay now for mole.

4.32g 1 mole/51.996g = .0831 mole

Correct?

• Chemistry again -

No, you have a math error.

moles= 5*E20/6.02E23=.000831 moles
mass=moles*51.996 which is not what you have.

• Chemistry again -

So mass would be .0432?

the reason why i got the problem completely wrong was because i got the mass wrong?

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