Chemistry: Stoichiometry

  • Thread starter dracolnyte
  • Start date
  • #1
28
0

Homework Statement


a sample of gas compound is made up only of B and H weighing 0.596g occupies 484 mL at STP. *then burned in excess O2, it yields 1.17g of H2O and all of the boron is converted to B2O3
what is a) its empirical formula? b) its molecular weight? c) its molecular formula? d) the weight of B2O3 produced?


The Attempt at a Solution


I kinda have an idea on how to solve this, i answered a) and b), which turns out to be
2BH2 and the molecular weight is 23.6378.

Now, I know that the molecular formula is just the empirical formula times an integer, and that integer is usually the molecular weight of the compound divided by 23.6378.

So i should be getting 0.596g/23.6378g? that doesnt seem right, did i do something wrong here?
 

Answers and Replies

  • #2
867
0
You need to divide the molecular weight by the empirical weight; that gives you the integer you multiply with the empirical formula.
 
  • #3
28
0
You need to divide the molecular weight by the empirical weight; that gives you the integer you multiply with the empirical formula.

Ya I know, I have found the molecular weight, but how do i find the empirical weight? isnt it just 0.596g as given?

0.596/23.63?
 
  • #4
Borek
Mentor
28,816
3,323
Empirical weight = molar weight of empirical formula.
 
Last edited by a moderator:
  • #6
Borek
Mentor
28,816
3,323
0.596 is not molar weight of empirical formula. It is weight of the sample.
 
Last edited by a moderator:
  • #8
867
0
You said you have the empirical formula, so just add up the weight of the elements in the empirical formula.
 

Related Threads on Chemistry: Stoichiometry

  • Last Post
Replies
2
Views
5K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
8
Views
9K
  • Last Post
Replies
1
Views
3K
  • Last Post
2
Replies
29
Views
20K
Replies
3
Views
10K
  • Last Post
Replies
3
Views
960
Top