# Chemical Forums

## Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: SamanthaMcOw on June 28, 2021, 05:54:23 PM

Title: 135 mM NaCl in 1000 L can you please confirm my calculation?
Post by: SamanthaMcOw on June 28, 2021, 05:54:23 PM
Hi Guys!

I need to prepare 135 mM of NaCl in 1000 ml, having just molecular weight, which is 58,443 g/mol.

I have calculated it: (135 mM * 58,443 g/mol)/1000 ml = 7,889805

My answer is 8g

is that correct?
Title: Re: 135 mM NaCl in 1000 L can you please confirm my calculation?
Post by: jeffmoonchop on June 28, 2021, 06:15:54 PM
Yep, but weighing 8g would give you 136.9mM. Depends how accurate you need to be.
Title: Re: 135 mM NaCl in 1000 L can you please confirm my calculation?
Post by: SamanthaMcOw on July 02, 2021, 05:31:20 AM
Thanks!

I am a bit "swimming" between mM and M as a unit.....so if I will have to prepare 135 M of NaCl in 1000 ml the answer would be the same?
Title: Re: 135 mM NaCl in 1000 L can you please confirm my calculation?
Post by: mjc123 on July 02, 2021, 06:07:54 AM
No. 135 mM = 0.135 M. You couldn't make a 135 M solution of NaCl (8kg/L).