March 28, 2024, 06:26:21 AM
Forum Rules: Read This Before Posting


Topic: help with solutions in lab for a personal project.  (Read 1712 times)

0 Members and 1 Guest are viewing this topic.

Offline trio

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
help with solutions in lab for a personal project.
« on: December 07, 2018, 05:09:45 PM »
I need to make a solution containing 45 g/L of Cu and 2 g/L of H2SO4. All of this in 1L of volume. I´ve calculated the amount of CuSO4*5H2O to add and the amount of acid at 98% purity. The problem comes when the samples are sent to chemical analisis the amount of H+ is waaaay higher than expected. Any feedback on why this is happening and how to fix it?? maybe the disolution of the solid is generating some acidity idk.


pd:this is a personal project on my hs and the analysis is donde by an external entity so idk what test the do to determine the concentrations of H+ and Cu.

Offline Enthalpy

  • Chemist
  • Sr. Member
  • *
  • Posts: 4041
  • Mole Snacks: +304/-59
Re: help with solutions in lab for a personal project.
« Reply #1 on: December 07, 2018, 05:29:42 PM »
Welcome, trio!

I don't understand how you could dissolve Cu (in water supposedly). CuSO4 is soluble but here you pretend to dissolve more of metallic Cu (or Cu2+ ions?) and less of the acid. The you also tell CuSO4 and H2SO4 in water, which would mean more acid moles than metal moles.

Could you double-check the figures, tell more clearly the masses or moles, and whether you mean Cu ions?

Offline trio

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
Re: help with solutions in lab for a personal project.
« Reply #2 on: December 07, 2018, 06:00:50 PM »
indeed every time I talked about Cu I meant Cu2+.

The task is to simulate a solution from a industrial process (which i dont want to go into much detail). This solution has the characteristic concentration of 45g/L Cu2+ and 2g/L H2SO4 (data that was researched).

 So in order to do this I added 176grams of CuSO4*5H2O and roughly 2grams of H2SO4 on to a liter of solution. But then the analysis came with waay more acid concentration than expected.

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27637
  • Mole Snacks: +1799/-410
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: help with solutions in lab for a personal project.
« Reply #3 on: December 07, 2018, 07:01:06 PM »
How was the amount of acid measured?

Solution that is just 45 g/L in Cu (be it Cu+ or Cu2+, doesn't matter) and 2 g/L in H2SO4 is impossible. You need an additional counterion to keep the solution electrically neutral. When you use CuSO4 this counterion is SO42-.
« Last Edit: December 08, 2018, 04:02:16 AM by Borek »
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline Enthalpy

  • Chemist
  • Sr. Member
  • *
  • Posts: 4041
  • Mole Snacks: +304/-59
Re: help with solutions in lab for a personal project.
« Reply #4 on: December 10, 2018, 04:43:01 PM »
Could it be that 2g/L H2SO4 count only the fraction that does not come from CuSO4?

Sponsored Links