July 17, 2024, 05:45:14 PM
Forum Rules: Read This Before Posting

### Topic: Probably pretty simple question from basics of chemical calculations.  (Read 1493 times)

0 Members and 1 Guest are viewing this topic.

#### Borek

• Mr. pH
• Deity Member
• Posts: 27744
• Mole Snacks: +1804/-411
• Gender:
• I am known to be occasionally wrong.
##### Re: Probably pretty simple question from basics of chemical calculations.
« Reply #15 on: June 26, 2024, 05:13:31 PM »
"Mixture of NaNO3 and Na2SO4 weights 5.37g and contains 1.61g of sodium. What is the mass percentage of NaNO3 in this mixture?"

Check that the given answer (45%) doesn't give 1.61 g of Na.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

#### windom626

• Regular Member
• Posts: 18
• Mole Snacks: +0/-1
##### Re: Probably pretty simple question from basics of chemical calculations.
« Reply #16 on: June 26, 2024, 05:14:25 PM »
To  Hunter2:
So as I have written:

N1*85+N2*142=5.37
N1*62+N2*96=3.76

Yes? Well we get
N1= 0.028 mole of NaNO3
N2= 0.020 mole of Na2SO4

This means - 0.028*85 = 2.38g of NaNO3
and 2.84 g of Na2SO4

This means

2.38 / 5.37 *100% = 44.3%

Which for me is now just a rounding up issue - and it's a correct answer.
Yes?

#### Borek

• Mr. pH
• Deity Member
• Posts: 27744
• Mole Snacks: +1804/-411
• Gender:
• I am known to be occasionally wrong.
##### Re: Probably pretty simple question from basics of chemical calculations.
« Reply #17 on: June 26, 2024, 05:19:28 PM »
N1*85+N2*142=5.37

Try with a correct value of 5.71
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

#### Borek

• Mr. pH
• Deity Member
• Posts: 27744
• Mole Snacks: +1804/-411
• Gender:
• I am known to be occasionally wrong.
##### Re: Probably pretty simple question from basics of chemical calculations.
« Reply #18 on: June 26, 2024, 05:19:42 PM »
Why not follow what I wrote.

Because it is an unnecessary detour that in no way makes solving the problem easier nor simpler?
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

#### windom626

• Regular Member
• Posts: 18
• Mole Snacks: +0/-1
##### Re: Probably pretty simple question from basics of chemical calculations.
« Reply #19 on: June 26, 2024, 06:31:41 PM »
Case closed. Both ways were correct. Thanks for answers. Forever I will remember this.

Did the next excercise, same idea, diffrent compounds I got it right in first aproach.

Thanks!