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Solutions Part 1
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Introduction and methods of expressing concentration

Shaillee Kaushal is teaching live on Unacademy Plus

Shaillee Kaushal
Faculty in Chemistry with a teaching experience of 14 years. Specialised in teaching for boards and competitions.

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  1. XII 02 Solutions- I

  2. SOLUTIONS Binary Ternary Quaternary

  3. Types of Solution:- S.No 1. Solute Gas Gas Gas Liquid Solvent Gas Liquid Solid Liquid Example Air Aerated water Hydrogen in palladium Alcoholin water benzene in toulene Mercury in Zn amalganm Sugar in water Alloys. 4 Liquid solid solid Solid liquid solid 7.

  4. Methods of Expressing the concentrations of a solution Mass percentage or Percent by mass: It is defined as the amount of solute in gram present in 100 gram ofthe solution. Mass percentage of solute- Mass of solute x 100 Mass of solution 1 Mass of solute x 100 Volume of xdensity solution of solution 10% solution ofsugar means 1 0 grams ofsugar is present in 100 gram ofthe solution. ii) Percent by volume: It is defined as the volume of solute in mL present in 100 mL solution. volume of solute volume of solution 100 iii Percent mass by volume: Mass of solutex100 volume of solution

  5. Parts per million (PPM: when the solute is present in trace quantities, it is convenient to express the concentration in parts per million (PPm) ppm = Mass of solute 10 PPm of S02 in air means 10mL of S02 is present in 106 mL of air 106 Mass of solution (v) Mole fraction:x It is defined as the ratio of number of moles of one component to the total number of moles of the solution. The sum of mole fraction is equal to mole fraction is independent of temperature of the solution

  6. (vi) Molalitv: 'm It is defined as the number of moles of the solute present in 1 kg of the solvent WAin kg np- number of moles of solute wA number of kilo-grams of the solvent m- we 100 WB of the solute MBXWA Mg = molar mass of the solute Wa = weight of the solvent in grams Relation between mole fraction and molality nB nA xA nA MBxWA Multiplying both sides by 1000 XB 1000 wB 1000 x 1000 (1-%)MA

  7. Molality and solubility are related as: Molality solubility X10 Molecular mass of the solute Mass of solute in granesx100 SolubilityMass of solvent (vii) Mola rity 'M' Number of moles of solute Number of litres of solution MBxVin mL) Let d density of solution x% = solute by mass MB Molarity of dilution:

  8. Molarity of mixing: Let there be three samples ofsolution (containing same solute and solvent) with their molarity M1M2,M3 and volumes V,V2.V3 respectively. These solutions are mixed molarity of the mixed solution may be given as Molarity depends upon temperature as it depends upon the volume 1M Molar solution 0.5M or M/2 Semi molar 0.1M or M/10 Decimolar 0.01 M or M/100 = Centimolar 0.001M or M/100 = millimolar Relation between molality and molarity: MB m M 1000 p density of solution m molalilty M molarity MB molar mass of solute

  9. Relation between molarity M' and mole-fraction: (vii) Normality: It is defined as the number of gram equivalent ofsolute present per litre ofsolution. ,N' = Number of gram equivalents of solute N'EN number oflitres ofthe solutio E equivalent mass of the solute WB = weight of the solute in grams. EBxV