1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Chemical arithmetics: Answers not matching

  1. Aug 4, 2014 #1
    Question: 2.0 g of a mixture of Na2CO3 and NaHCO3 was heated when its weight reduced to 1.876 g. Determine the percentage composition of the mixture.

    Attempt: Here is my attempt:


    Problem: My answers do not match those of the text. More critically, the procedure I've adopted is itself inconsistent with that outlined in the text: the "its" in the first line of the problem statement is interpreted in the text as the mass of Na2O alone, whereas I am considering it to be the combined mass of the products (see first 2 lines - chemical reactions - of my attempt above).

    Whose interpretation is correct?

    Would appreciate some thoughts.

    Best regards,
    Last edited: Aug 5, 2014
  2. jcsd
  3. Aug 5, 2014 #2
    For those discouraged to answer, I've removed links to images in my original post and inserted the appropriate image instead.

    Last edited: Aug 5, 2014
  4. Aug 5, 2014 #3


    User Avatar

    Staff: Mentor

    I don't get the light blue comment nor the equation after it.

    Think again: what are the reactions taking place and what are the final products?
    Last edited: Aug 5, 2014
  5. Aug 5, 2014 #4


    User Avatar
    Homework Helper
    Gold Member

    Not gone through. Unfortunate fact: someone else's arithmetic is as attracting as someone else's unmade bed. Despite your colouring etc. is thoughtful and helpful and as good as it gets! :approve:

    However I noticed that in your first equation Na2CO3 went to Na2O. In the second you show Na2CO3 as a product that just stays there. Why wouldn't that also go to Na2O ?
    Last edited: Aug 5, 2014
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted