Physical Chemistry> molarity...

what is the relationship between molarity and molality

himani raina , 14 Years ago

Grade

15 Answers

RAGHVAN DAS

Molarity=(no of moles of solute)/(volume of solution in litrs)

while molality=(moles of solute)/(wt of solvent in kg)

the above two have a relationship as-

molality= Molarity/(density of solution-Molarity*molecular wt of solute)

m = M / (ρ - M x mw A)

apply this relation to solve numericals when density of solution is given...

Last Activity: 14 Years ago

Ritvik Gautam

Molarity is defined as number of moles divided by the volume (in liters).

whereas

Molality is defined as the number of moles divided by the mass of the solution (in kg).

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Last Activity: 14 Years ago

Jaya IITK

molarity = no. of moles ofsolute/vol of soln. in litre

molality = no. of moles of solute/ wt. of solvent.

if density of solvent is given we can find out relation between molality and morality..

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Last Activity: 14 Years ago

abhay prakash

Molality = molarity × 1000/consentrtion(g/l) – molarity × molar massUnite of LHS = mol /kgUnite of RHS = ( mol/liter)/(g/l – g/l) × 1000 = (mol/liter )/ (g/liter) × 1000) =mol/g × 1000 = mol/kgAccording to the unite of LHS and RHS this formula is right use this formula in numerical for qick and write answer

Last Activity: 9 Years ago

Rahul

Molarity(M)=m×d ______ 1+ m×M2 ________ 1000Where M2=molar mass of solute and d=density of the solution

Last Activity: 8 Years ago

anjaly

molarity is defined asno of moles of solute ÷volume of solution in litresmolality is defined as nomolesof solute ÷mass of the solvent in kilogramM(w÷1000+1÷M) = dwhere d is density

Last Activity: 8 Years ago

shubham

1÷molarity=1/density{1/molality+molecular weight of solution/1000} this is an easier way to find the relation between molality, molarity and density of solution

Last Activity: 8 Years ago

The iit guy

d=M(1/m+M2/1000)Where d is density of solution,M is molarity,m is molality,M2 is molecular mass of solute

Last Activity: 8 Years ago

kunal arora

Let M be the molarity Let m be the molality Let V be the volume of the solventLet X be the mass of solvent Let n be the moles of solute By formula, M = n/V ----(1)And By formula, m = n/X ----(2)Equating (1) & (2) for ` n ` - - > We get, MV = mX So molarity, M = mX/V And molality m = MV/X ---×----×-----×----P |_ € @ $ £ @ p p r ? \/ € The answer if you feel it helpful....Thank u

Last Activity: 8 Years ago

Rahul kurup

pls read full answer.
The relation between molarity and molality is as follows:-
1/M=1/d(1/m+K1/1000)
Here M=molarity
K1=molar mass of solute
m=molality
d=Density of solution
DERIVATION:-
Refer to above symbols and these symbols to understand derivation:-
n=moles of solute
V=volume of solution
WA=mass of solute
WB=mass of solvent
WS=mass of solution

Now m=n/WB
M=n/V and d=WS/V so V=WS/d.On substituting in M=n/V we get M=n/(WS/d)=(n*d)/WS
now m/M=(n/WB)/((n*d)/WS)
m/M=(n*WS)/(WB*n*d)
m/M=WS/(WB*d)
m/M=(WA+WB)/(WB*D).This is bcoz WS=WA+WB
m/M=(WA)/(WB*d)+(WB)/(WB*d)
m/M=(n*K1)/(WB*d*1000))+(1/d).This is bcoz n=given mass/molar mass.So n*molar mass=given mass.Therefore n*K1=WA.We divide K1 by 1000 to convert the molar mass(which is in grams) to kg.Now:-
m/M=(n/WB)*(K1/d*1000)+(1/d)
m/M=(m*K1/d*1000)+1/d.This is bcoz m=n/WB
m/M=1/d(((m*K1)/1000)+1)
1/M=1/d*m(((m*K1)/1000)+1)
1M=1/d((K1/1000)+1/m) .
Hence we derive the relation between molarity and molality.
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Last Activity: 7 Years ago

Anuj

Molality means 1 mol solute in 1 kg solvent Or 1000g solvent [ | m=mass÷ molar mass ~ mass = mMb ] | Or 1000g + m×Mb g solution. |

= 1000 + m×Mb ÷ density . |

M(molarity) = (mol of solute × 1000) ÷ volume in ml

M = 1000 × density × m ÷ (1000+mMb)

Last Activity: 7 Years ago

Prachi

d=M[1/m+molecular weight /1000]

Where,

d=density

M=molarity

m=molality

Here,

The formula of m=Wb/Mb×Wa(in kg

)

M=Wb/Mb×V(in litre)

And d=density=m/V

Where m=mass of given object

V=volume

Last Activity: 7 Years ago

ABHISHEK ANAND

let us take 1000ml of solution with density=P g cm^-1(rho) and molarity be M

mass of solution=1000P

let the molar mass of solute be M₂

mass of solute=M*M₂

mass of solvent=1000P-MM₂

MOLALITY=(M/1000P-MM₂)*1000=1000M/1000P-MM₂

MOLALITY(m)=M/(P-MM₂/1000)

1/m=(P-MM₂/1000)/M

1/m=P/M-M₂/1000

P/M=1/m+M₂/1000

Last Activity: 6 Years ago

Somanorani Ningthoujam

Molality(m) = Molarity(M) / 1000 d - M.Mb, where d is density of solution in gram per mole and Mb is molar mass of solute

Last Activity: 6 Years ago

Rishi Sharma

Hello students,
The solution of the above problem is attached.
I hope the solution will solve all your doubts.
Thank You,
All the Best for the Exams. 645-1410_WhatsApp Image 2020-06-04 at 8.11.48 PM.jpeg