Question

a solution of sucrose (c12h22o11) contains 13.5g in 100 ml of the solution the density =1.05kg/L calculate the molality of the solution

Answer 1

@shivam_bhalla plzz help

Answer 2

Show your working out/ attempt/ approach you have taken please.

Answer 3

If you are totally clueless, then read yur textbook and come back again

Answer 4

molality=no of moles/in 1kg of solvent

Answer 5

Yes. So what is your no of moles ??

Answer 6

moles=given wg/molar mass

Answer 7

you know the molar mass of substance , right?? Calculate and tell me the molar mass

Answer 8

mm=342

Answer 9

right. Now how will you find given wt.?? Any ideas ??

Answer 10

no

Answer 11

(Tip : see the information given to you in the question that you haven't used yet)

Answer 12

13.5

Answer 13

and density. Right?? Now do you know the relation between density,mass and volume ??

Answer 14

d=m/v

Answer 15

Great. Now find your m from that relation and your m will be your given mass

Answer 16

m=d*v

Answer 17

So you will get your number of moles now. Next you know the volume of solution in litres and hence you know yourr molarity

Answer 18

m=0.105

Answer 19

Yes @ openstudy/ You found the given mass. Now follow what I told you in the last comment

Answer 20

Sorry. There was a typo in my 2nd last comment

Answer 21

ok then wat to do

Answer 22

So now find your number of moles now.

Answer 23

0.105/342= 3.05161 i am getting while i divided this.... i know this is not possible can u do it

Answer 24

http://www.google.com/search?q=0.105%2F342&ie=utf-8&oe=utf-8&client=ubuntu&channel=fs

Answer 25

Ok. So now you found your number of moles(from above link). So what is your molality now??

Answer 26

hey i got a number which is very small and it does not match to my option

Answer 27

the answer should be ~0.43

Answer 28

Let me check

Answer 29

ok

Answer 30

@shivam_bhalla r an indian ....if u r which state??

Answer 31

we have nt used 13.5 gm i think there is a mistake

Answer 32

I got it now

Answer 33

can u show that plz

Answer 34

One question. The density is given for solution, right ??

Answer 35

yes

Answer 36

density =1.05kg/L

Answer 37

Is the answer equal to 0.3947 ??

Answer 38

Yes. We made a mistake in calculating given mass. The given mass is actually 13.5 gm

Answer 39

the ans=0.43

Answer 40

@ujjwal , you are making confusion in calculating wt of solvent

Answer 41

The number of moles is http://www.google.com/search?q=0.105%2F342&ie=utf-8&oe=utf-8&client=ubuntu&channel=fs#hl=en&client=ubuntu&channel=fs&sclient=psy-ab&q=13.5%2F342&oq=13.5%2F342&aq=f&aqi=g-bCK8&aql=&gs_l=serp.3..0i8i33i30l8.339422.341004.7.341131.4.4.0.0.0.0.678.928.0j2j5-1.3.0...0.0.jLanBWGKmSk&psj=1&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=3fd8129ac5126995&biw=1024&bih=627

Answer 42

the molality=0.39

Answer 43

that is wrong.............

Answer 44

Guys, wt of solvent is not 0.1 gm

Answer 45

then wat???

Answer 46

*kg

Answer 47

If ans is 0.39, use relation g/l =molarity*molecular wt
You don't need density
here g/l=13.5/0.1

Answer 48

i think we have to do something with density

Answer 49

No.. we don't need density.. molarity has nothing to do with density.. use the relation i provided.. you will get answer 0.39 M

Answer 50

it is molality

Answer 51

Volume is clearly stated to be 100ml=0.1l

Answer 52

mass of solute = density * volume = 1.05 * 0.0135

Answer 53

ok then

Answer 54

I will have to sleep early. Sorry. @JFraser will help you

Answer 55

I am not getting it at the moment . ;(