IWantSmile

10+ Year Member
5+ Year Member
Sep 5, 2008
121
0
Status (Visible)
  1. Dental Student
hi, I need a help again... please.... No wonder I am not good at GChem.:(

Here is the question: The percentage of an element X equal to 77.4%, 63.2%,69.6%, and 72%. If the compund with 77.4% X is XO, what is X, and what are the other compounds?

I will post the answer later.

Thanks all in advance!
 

IWantSmile

10+ Year Member
5+ Year Member
Sep 5, 2008
121
0
Status (Visible)
  1. Dental Student
Ops! I figured it out the answer.
For someone who want to do anyway, here is the answer: MnO, MnO2,MnO3, and MnO4.
 

Contach

10+ Year Member
Jun 6, 2008
1,497
127
NYC
Status (Visible)
  1. Attending Physician
wow. why is it the hardest thing in the world to find a freaking periodic table of elements with atomic mass online...

that just took 5 minutes of my life.
 
About the Ads

supraman

Boston Celtics
10+ Year Member
7+ Year Member
Oct 30, 2005
1,539
3
Status (Visible)
  1. Dental Student
wow. why is it the hardest thing in the world to find a freaking periodic table of elements with atomic mass online...

that just took 5 minutes of my life.

google.com/images
periodic table
view extra large images
click the pic
:confused:
 

IWantSmile

10+ Year Member
5+ Year Member
Sep 5, 2008
121
0
Status (Visible)
  1. Dental Student
ok, then i will not begin.
why don't you explain how it was done to ACTUALLY help the others?

OK.

Given question: The percentage of an element X equal to 77.4%, 63.2%,69.6%, and 72%. If the compund with 77.4% X is XO, what is X, and what are the other compounds?

I started 77.4% X is XO. If 77.4% is X then O is 22.6%. I used the ratio of X: O = 3.4 : 1. I know the MW of O is 16g; so, 16g * (3.4) = 54.9 g X
I looked at the periodic table for finding the element of X. That is Manganese, Mn.

For the 63.2% , If Mn is 63.2% then O is 36.8%. The calculation is basically same as above, using the ratio of Mn : O = 1.7 : 1
I know from previous information that MW of O has been increased; 2(16g O)* (1.7) (Mn/O)= 54.9g Mn ; MnO2.

Now you can try with other to get answer 69.6% and 72%.
 
About the Ads
This thread is more than 12 years old.

Your message may be considered spam for the following reasons:

  1. Your new thread title is very short, and likely is unhelpful.
  2. Your reply is very short and likely does not add anything to the thread.
  3. Your reply is very long and likely does not add anything to the thread.
  4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
  5. Your message is mostly quotes or spoilers.
  6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
  7. This thread is locked.