Question

An alloy has Fe, Co , Mo in a composition of 71%, 12%, 17% respectively. How many cobalt atoms are there in a cylinder of radius 2.5 cm and length 10 cm .The density of the alloy is 8.2 g/ml.[At.wt Co=59]

Answer 1

mass= density * volume
density is given
volume = pi r^2 h
fine mass
12% of mass is the final answer

use appropriate units.

Answer 2

find*

Answer 3

oh.. we should take v of cylinder as volume?

Answer 4

yep

Answer 5

and they've asked number of cobalt atoms..how is that 12% of mass?

Answer 6

ahh okay
12% of that = mass of cobalt

atoms in 1 mole of cobalt = avagadros no.
atoms in given mass = ?

Answer 7

12 % of that? what is that? no.of atoms? or no.of moles?

Answer 8

looks like 12% by mass

Answer 9

12% of that , that'll give mass of cobalt in the compound

Answer 10

what is 'that'?

Answer 11

"that" is the mass of the cylinder I think

Answer 12

that is mass of the compound in the given volume -_-

Answer 13

ok so mass of the alloy..right?

Answer 14

yo B|

Answer 15

look..im sorry if u feel im dumb..but hw am i supposed 2 find mass of alloy?

Answer 16

mass = density * volume -_-

Answer 17

Volume? again volume of cylinder?

Answer 18

volume =pi*radius^2*height

Answer 19

@ Peter14 I KNOW THAT...im askin if volume of alloy is same as volume of cylinder..

Answer 20

yes, because the alloy is in the shape of the cylinder

Answer 21

the allow is in in the cylinder, so there volumes must be equated

Answer 22

oh ok...k i got this..i have 2 more...can i post them now??

Answer 23

sure
shub, you take one, i'll take the other

Answer 24

lol..
:D
(Y)

Answer 25

dont worry i can only post one-by-one...

Answer 26

start separate threads

Answer 27

One-by-one is easier for me..one itself is hard to understand..2 means gone!

Answer 28

ok, that works