April 20, 2024, 05:01:57 AM
Forum Rules: Read This Before Posting


Topic: Quick question  (Read 3052 times)

0 Members and 1 Guest are viewing this topic.

Offline zeshkani_usa

  • Regular Member
  • ***
  • Posts: 13
  • Mole Snacks: +0/-1
Quick question
« on: January 16, 2013, 09:03:24 PM »
Hi there,

I have 1 question I have done it just wondering some feed back if this is right.

1.Calculate the Density of NaCl at 20C in [lbm/ft3]

here i used the Specific gravity of NaCl and which was 135lbm/ft3 multiply by 62.43lbm/ft3 which is the ref. for most soilds and liquids but this gives a very large density of 8370 lbm/ft3
but i was wondering if this could be done by using the V=nRT/P plug V into the D=M/V => D=m/(RT)
since there is no mention of the weight of NaCl i assumed 1mole
by doing this i get this answer 1.497022809933 lb/ft3 to get lbm/ft3 i just divied 1.49/32.2 =0.0357lbm/ft3
why is there such a difference between these 2 answers
is there a better method of doing this?


Offline sjb

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 3652
  • Mole Snacks: +222/-42
  • Gender: Male
Re: Quick question
« Reply #1 on: January 17, 2013, 02:37:33 AM »
Hi there,

I have 1 question I have done it just wondering some feed back if this is right.

1.Calculate the Density of NaCl at 20C in lbm/ft3

here i used the Specific gravity of NaCl and which was 135lbm/ft3 multiply by 62.43lbm/ft3 which is the ref. for most soilds and liquids but this gives a very large density of 8370 lbm/ft3
but i was wondering if this could be done by using the V=nRT/P plug V into the D=M/V => D=m/(RT)
since there is no mention of the weight of NaCl i assumed 1mole
by doing this i get this answer 1.497022809933 lb/ft3 to get lbm/ft3 i just divied 1.49/32.2 =0.0357lbm/ft3
why is there such a difference between these 2 answers
is there a better method of doing this?

What is the full name of the unit you are using? lbm/ft3? Check your units, what is the name of the formula you are using in the V=nRT/P strp?

Sponsored Links