Chemistry, asked by aryamavaishnava, 10 months ago

Molality of a solution in which 0.00585g of NaCl is dissolved in 500g of water.

Answers

Answered by ItzArchimedes
5

Solution:

Using molality formula

m = w/GMW × 1000/W(g)

Where

  • m : molality = ?
  • w : mass of solute = 0.00585 g
  • GMW : Gram molecular weight of solute = NaCl = 23 + 35.5 = 58.5
  • W(g) : weight in gram of solvent = 500g

Substituting the values we have

→ m = 0.00585/58.5 × 100/500

→ m = 0.0001 × 0.2

m = 0.00002 = 2 × 10-

Hence , molality of the solution = 2 × 10- mol/g

Concept:

Molality : The molality of a given solution (m) is defined as "the number of moles of the the solute present in one kg or 1000g of solvent"

In other form:

m = n/W(kg)

Here,

n = mass of solute(w)/GMW of solute

Substituting we have

m = w/GMW × 1/W(kg)

Into grams

m = w/GMW × 1000/W(g)

m = n/W(kg) = w/GMW × 1/W(kg) = w/GMW × 1000/W(g)

SI ( Standard international ) unit : mol/kg

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