.Number of molecules in 8.457×10−2

Answer 1

Are you solving for molecules or are you solving for moles?

If for molecules/atoms/parts you can set it up this way:

1 mol = 6.022E23 molecules/atoms. of any substance

8.457x10^-2 or 8.457E-2 mol = X molecules/atoms/parts

Cross multiply and solve for x:

X= 6.022E23*8.457E-2 = 5.0928x 10^22 molecules.

If you are solving for moles with number given you would set it up this way:

1 mol = 6.022E23 molecules/atoms/parts

X mol = 8.457E-2 or 8.457x10^-2.

E-2 and x10^-2 is just another way of saying the same thing. When you cross multiply and solve for X, you get:

X*6.022E23 = 1*8.457E-2

X= 8.457E-2/6.022E23

X = 1.404E-25

This is a very small number because it has a -25 as the exponent.

More than likely you may have been asking for the number of molecules if given 8.457x10^-2 moles because this is usually a typical numerical expression for moles. Please let me know if you meant moles for your numerical expression. If you did, then the first solution would be your best bet. Yielding 5.0928E22 molecules,. 5.093E22 or 5.093 x10^22 for sig fig purposes.