Expressing Concentration of Solutions | Solutions | Notes | Summary - Zigya

Book Store

Download books and chapters from book store.
Currently only available for.
CBSE

Previous Year Papers

Download the PDF Question Papers Free for off line practice and view the Solutions online.
Currently only available for.
Class 10 Class 12
Advertisement

Solutions

Quickly browse through questions and notes on related topics. You can also download and read this topic offline.


Advertisement

Expressing Concentration of Solutions

1) Mass percentage (w/w): The mass percentage of a component of a solution is defined as:

equals space fraction numerator Mass space of space the space compnent space in space the space solution over denominator Total space mass space of space the space solution end fraction space straight x space 1002) Volume percentage (v/v): The volume percentage is defined as:

Volume percent sign space of space straight a space component space equals space fraction numerator Volume space of space the space component over denominator Total space volume space of space Solution end fraction space straight x space 100

3) Mass by volume percentage (w/v):

space equals space fraction numerator mass space of space solute space left parenthesis straight g right parenthesis over denominator volume space of space solution space left parenthesis mL right parenthesis end fraction space straight x space 100

Common units for w/v% concentration are g/100mL (%)

4) Parts per million: When a solute is present in trace quantities, it is convenient to express concentration in parts per million (ppm) and is defined as:

equals fraction numerator Number space of space parts space of space the space component over denominator Total space number space of space parts space of space all space components space of space the space solution end fraction space straight x space 10 to the power of 6

5) Mole fraction of a component :


equals fraction numerator Number space of space moles space of space the space component over denominator Total space number space of space moles space of space all space the space components end fraction

The used symbol for mole fraction is x and subscript used on the right-hand side of x denotes the component.
For binary solution: The number of moles of A and B are nA and nB respectively so,

straight x subscript straight A space equals space fraction numerator straight n subscript straight A over denominator straight n subscript straight A plus straight n subscript straight B end fraction space semicolon space straight x subscript straight B space equals space fraction numerator straight n subscript straight B over denominator straight n subscript straight A plus straight n subscript straight B end fraction
In binary solution xA + xB =1

6) Molarity: Molarity (M) is defined as a number of moles of solute dissolved in one litre (or one cubic decimetre) of the solution.

straight M space equals space fraction numerator Moles space of space solute over denominator Volume space of space solution space in space litre end fraction

Unit of Molarity are mol L-1, mol dm-3

7) Molality: Molality (m) is defined as the number of moles of the solute per kilogram (kg) of the solvent and is expressed as:

straight m space equals space fraction numerator Moles space of space solute over denominator Mass space of space solvent space in space kg end fraction

Unit of molality are mol kg-1

8) Normality (N) is defined as the number of mole equivalents per liter of solution:

straight N space equals fraction numerator number space of space mole space equivalents over denominator 1 space Litre space of space solution end fraction

Molarity (M), Molality(m) relates the amount of solute to the total volume of solution; however, normality is specifically used for acids and bases.

Advertisement