A compound has an empirical formula of CH2. It has a molecular mass of 56.1. What is the molecular formula?



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jerichorayel's profile pic

Posted on (Answer #1)

Step 1: We can start solving this problem using the molecular mass of CH2.

For CH2

   C =12.011 g/mole

+ H = 1.008 g/mol x 2


     14.027 g/mole

Step 2. Get the ratio of the empirical mass and the molecular mass.

= 56.1/14.027

= 3.999 = 4

Step 3. Multiply the resulting number with the subscripts of the empirical formula.

4(CH2) = C4H8

The molecular formula is C4H8.

ayl0124's profile pic

Posted on (Answer #2)

An empirical formula is the simplest ratio of elements in a molecular formula. CH2 is an empirical formula for methane and other hydrocarbon compound. Think of your compound as `"C_nH_2n"` .

Find the mass of CH2. 

`(12.01"g" xx 1) + (1.008"g" xx 2) = 14.026"g"`

Divide this mass into your molecular formula's mass.

`(56.1"g")/(14.026"g") = 3.999 ~~ 4`

Multiply this value with your empirical formula.

`(4 xx 1"C") + (4 xx 2"H") = "C_4H_8"`

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