January 28, 2020, 06:00:36 AM
Forum Rules: Read This Before Posting


Topic: Dilute 20% solution to create 3 litres of 1% solution  (Read 170 times)

0 Members and 1 Guest are viewing this topic.

Offline saparama

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
Dilute 20% solution to create 3 litres of 1% solution
« on: January 16, 2020, 02:58:15 PM »
The problem is: We have a 20% solution of NaCl and we want to create 3 litres of 1% NaCl solution. Question is how many litres of 20% solution and how many litres of water should we use to create such thing.

It was on my exam and I tried to use c1.V1 = c2.V2    From  equation m1.w1 = m2.w2 i found out that m1 = 0,05.m2  but that is all I got. Can someone please help me? How should I continue? Does this problem have a solution?
« Last Edit: January 16, 2020, 04:25:55 PM by saparama »

Offline chenbeier

  • Full Member
  • ****
  • Posts: 737
  • Mole Snacks: +63/-17
  • Gender: Male
Re: Dilute 20% solution to create 3 litres of 1% solution
« Reply #1 on: January 16, 2020, 04:10:27 PM »
Use cross rule

20.             1 weight part
          1
0.               19 weight part
______________
                    20 weight part = 3 kg

You need the specific gravity to convert to volume.

If you calculate in mass 3 kg 1% solution  = 20 weight parts

You need 150 g 20% solution ( 1 weight part) and 2,85 kg (19 weight part) of water.

Offline saparama

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
Re: Dilute 20% solution to create 3 litres of 1% solution
« Reply #2 on: January 16, 2020, 04:18:01 PM »
Use cross rule

20.             1 weight part
          1
0.               19 weight part
______________
                    20 weight part = 3 kg

You need the specific gravity to convert to volume.

If you calculate in mass 3 kg 1% solution  = 20 weight parts

You need 150 g 20% solution ( 1 weight part) and 2,85 kg (19 weight part) of water.

Thank you very much for you answer but I have a question. They wanted the answer in volumes. Can I use 0,150 litres and 2,85 litres?

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 25444
  • Mole Snacks: +1668/-398
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Dilute 20% solution to create 3 litres of 1% solution
« Reply #3 on: January 16, 2020, 05:15:23 PM »
These will be only approximate, density of the 20% NaCl solution is around 1.15 g/mL, so 150 g is quite far from being 150 mL,

If you were not given densities 150 mL is your best bet though.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Sponsored Links