Register to reply

Chemical arithmetics: Answers not matching

by wirefree
Tags: answers, arithmetics, chemical, matching
Share this thread:
wirefree
#1
Aug4-14, 11:55 PM
wirefree's Avatar
P: 32
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,
wirefree
Phys.Org News Partner Science news on Phys.org
'Office life' of bacteria may be their weak spot
Lunar explorers will walk at higher speeds than thought
Philips introduces BlueTouch, PulseRelief control for pain relief
wirefree
#2
Aug5-14, 04:45 AM
wirefree's Avatar
P: 32
For those discouraged to answer, I've removed links to images in my original post and inserted the appropriate image instead.

Regards,
wirefree
Borek
#3
Aug5-14, 07:02 AM
Admin
Borek's Avatar
P: 23,724
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?

epenguin
#4
Aug5-14, 07:05 AM
HW Helper
epenguin's Avatar
P: 1,991
Chemical arithmetics: Answers not matching

Quote Quote by wirefree View Post
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,
wirefree
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!

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 ?


Register to reply

Related Discussions
Closest Matching Chemical Fingerprint -what analysis? Set Theory, Logic, Probability, Statistics 3
Arithmetics problem Calculus & Beyond Homework 5
Arithmetics in Z Linear & Abstract Algebra 3
Tertiary Arithmetics General Math 1
Am I getting the correct answers for these Chemical Equilbium (I have a test tommorow Chemistry 2