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Molecular Weight Calculator
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The molecular weight of a substance expresses the relative mass of its molecule in composition to some arbitrarily selected standard. Molecular weight in chemistry is considered a simple matter being just the weight of one mole of the compound. The molecular weight of a substance is pure number having no unit.

$Molecular\ weight = \frac{Mass\ of\ 1\ molecule\ of\ the\ substance}{Mass\ of\ 1\ atom\ of\ hydrogen\ (H=1)}$
For a given known compound it is easily calculated as the sum of the atomic masses of the constituent atoms in the molecular formula.

Below is given a default molecular formula, you can just see how the molecular formula is calculated using the calculator.

 

Steps for Molecular Weight Calculator

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Step 1 :  

Read the problem and find out the molecule whose molecular weight has to be determined.



Step 2 :  

From the chemical formula of the given element the molecular weight can be calculated.



Problems on Molecular Weight Calculator

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  1. The chemical formula for anhydrous codeine is C18H21NO3. Calculate the mass of 0.01 moles of the drug. [Data: m(C) = 12.01 gmol-1; m(H) = 1.008 gmol-1; m(N) = 14.01 gmol-1; m(O) = 16.00 gmol-1]


    Step 1 :  

    First we determine the molecular molar mass from the chemical fomula.



    Step 2 :  

    m(C18H21NO3) = 18 $\times$ 12.01 + 21 $\times$ 1.008 + 1 $\times$ 14.01 + 3 $\times$ 16.00


    = 299.36 gmol-1



    Answer  :  

    The molecular weight of C18H21NO3  = 299.36 gmol-1



  2. Calculate the molecular weight of hexane.


    Step 1 :  

    The chemical formula for hexane is C6H14.



    Step 2 :  

    m(C6H14) = 6 $\times$ 12.01 + 14 $\times$ 1.008


    = 86.175 gmol-1



    Answer  :  

    The molecular weight of C6H14 = = 86.175 gmol-1



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