Question

atomic weight of two element (a) and (b) are 32 and 16 respectively they combine to give two gases ab2 and ab4 and the mixture is found to have a vapour density of 38.4 the number of moles of ab2 in 50 moles of the mixture is ??

Answer 1

Ok. The very first step is to realize that for gases, we can approximate the atomic weight to the density.

Answer 2

Everything else, I completely forget.

Answer 3

molar mass = 2* vapour density

Answer 4

options are 10 20 30 40

Answer 5

the answer is 30

Answer 6

what is ab2, and ab4?

Answer 7

a is an element and b is another element ab2 is its formula

Answer 8

I don't think I can help you, or maybe i just don't know what you are talking about.. Sorry :(

Answer 9

Wait, I might have it. Give me a sec.

Answer 10

ok

Answer 11

ab2 and ab4
molar mass of
ab2=64
molar mass of
ab4=96

Answer 12

Sulfur and Oxygen

Answer 13

x+y=50 , where x is the amount in moles of ab2, and y is the amount in moles of ab4

Answer 14

yes it is sulphur and oxygen

Answer 15

Then,
64y=96x

Answer 16

Simplify that by dividing by 32
2y=3x

Answer 17

x+y=50
then,
2x+2y=100,
or,
2x+3x=100,
so, x=20, and y=30

Answer 18

No, I got it all wrong. Give me a second.

Answer 19

(64*c+92*d)/(c+d)=76.8
c+d=50
I thiiink that should be right, although I'm not sure.

Answer 20

you'll want to solve for d, I think.

Answer 21

yes

Answer 22

i did nt understand that step (64*c+92*d)/(c+d)=76.8

Answer 23

now i understood plzz go on with ur answer

Answer 24

Ok. I think it's because I got my equations wrong again.

Answer 25

Say that c:d= number of ab2 molecules: number of ab4 molecules.

Answer 26

ok

Answer 27

Then, 64c+96d=2*38.4
c+d=1, because the concentration of all of the molecules must be 1.

Answer 28

ok

Answer 29

Ok, I might make a lot of mistakes. :S

Answer 30

32d=76.8-64
d=(12.8)/32
c=1-(12.8/32)
now, find c*50

Answer 31

i did nt understand

Answer 32

Set c to the concentration of ab2
Set d to the concentration of ab4
Then, c+d must be 1, because the solution is completely made up of ab2 and ab4.
Now, 64c+96d=2*38.4,
solve for c, and d. c and d are concentrations, not actual values, so we must multiply c*50 to get our answer.

Answer 33

Took me long enough, but I finally have it :D

Answer 34

ha...haaa thanzzzz

Answer 35

You got it? :)