1.6 Chemical Calculations

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Chemical Calculations

In chemical calculations, we calculate number of moles and number of particles of a given mass of a substance or vice versa. These calculations are based upon mole concept. Let us have a few examples of these calculations.

Calculating the number of moles and number of particles from known mass of a substance.

First calculate the number of moles from given mass by using equation

Number of moles = known mass of substance/molar mass of substance

Number of particles from the calculated number of moles with the help of following equation:

Number of molecules = (number of moles)(6.02 X 1023)

 Mole-Mass Calculation

In these calculations, we calculate the number of moles of a substance from the known mass of the substance with the help of following equation:

Number of moles = known mass of substance/molar mass of substance

When we rearrange the equation to calculate mass of a substance from the number of moles of a substance we get,

mass of substance(g) = number of moles X molar mass(g)

Mole-Particle Calculation

In these calculations, we can calculate the number of moles of a substance from the given number of particles. (These particles are the atoms, molecules or formula units).

Number of moles = (given number of particles)/(Avogadro's Number)
Number of moles = (given number of particles)/(6.02 X 1023)
On rearranging above equation we get,
Number of Particles = (Number of moles) X (6.02 X 1023)

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Hello, this is Misbah ud Din a student of STEM. This is my blog chemisTREEpk which provides a vast knowledge about Chemistry(and sometimes other sciences) fully free.

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