calculations- molar concentrations

[Aka]

Hi, I need help with this question

 

what is the molar concentration of 0.50 mol of NaCl dissolved in 0.30L of solution?

 

=moles of solute/leters of solution

=0.50mol/0.30L

=1.7 mol/L

 

Is this correct?

 

and

 

what mass of solute is present in 1.00L of 0.045 mol/L of Ca(oH)2, solution

 

I have no idea how to do this one

[hybrid04]

For the first one im assuming you rounded up from 1.6666666 so yes that is correct. The second one is pretty much the same of the first.

 

(.045 mol/L) (1.00L)= # of mol

(#of mol) (molar mass)= g solute.

[Aka]

thanks for your help