Calculation problem

Chemistry and homework help forum.

Organic Chemistry, Analytical Chemistry, Biochemistry, Physical Chemistry, Computational Chemistry, Theoretical Chemistry, High School Chemistry, Colledge Chemistry and University Chemistry Forum.

Share your chemistry ideas, discuss chemical problems, ask for help with scientific chemistry questions, inspire others by your chemistry vision!

Please feel free to start a scientific chemistry discussion here!

Discuss chemistry homework problems with experts!

Ask for help with chemical questions and help others with your chemistry knowledge!

Moderators: Xen, expert, ChenBeier

Post Reply
ned_yas
Jr. Member
Jr. Member
Posts: 7
Joined: Mon Nov 01, 2021 3:45 am

Calculation problem

Post by ned_yas »

Hi people,

I'm trying to solve the following problems:

Problem 1:
1) How many grams HCl with mass fraction ω=36,5 % will fully dissolve 6 g Mg?
2) What's the mass fraction ω of MgCl2 in the formed solution?

For 1) I've calculated that 18,25 g HCl will fully react 6 g Mg - is this correct?
For 2) will the MgCl2 solution have ω=36,5 %? - is this correct?

Problem 2:
How many grams HCl with ω=30 % are needed to neutralise 500 ml NaOH solution with density ρ=1,2 g/ml and ω(NaOH)=10 %?
My calculations give 182,5 g HCl needed to neutralise the given amount of NaOH - is this correct?

Thanks for verifying and helping in advance.

Greetings,
Ned
User avatar
ChenBeier
Distinguished Member
Distinguished Member
Posts: 1542
Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

Re: Calculation problem

Post by ChenBeier »

1) you calculated the 100% of HCl, not 36,5%
Second one is also wrong
2) is correct
ned_yas
Jr. Member
Jr. Member
Posts: 7
Joined: Mon Nov 01, 2021 3:45 am

Re: Calculation problem

Post by ned_yas »

Yes, many thanks @ChenBeier - meantime I realised my mistake and corrected - it should be for 1) 50 g solution of HCl, and for 2) 42,8 % MgCl2 :)

Greetings,
Ned
User avatar
ChenBeier
Distinguished Member
Distinguished Member
Posts: 1542
Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

Re: Calculation problem

Post by ChenBeier »

Now it is correct.
ned_yas
Jr. Member
Jr. Member
Posts: 7
Joined: Mon Nov 01, 2021 3:45 am

Re: Calculation problem

Post by ned_yas »

ChenBeier wrote: Mon Nov 01, 2021 10:57 am Now it is correct.
Many thanks for confirming!
Post Reply