Question

The empirical formula for two compounds that have very different properties (one tastes very sour and the other very sweet) is ch2o. if the molar mass of compound a is 60.05 g/mol and compound b is 180.16 g/mol, what are the molecular formulas for these compounds, respectively?

Answer 1

Answer: Molecular formula for compound a: $C_2H_4O_2$

Molecular formula for compound b: $C_6H_{12}O_6$

Explanation:

Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.  

Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.

For empirical formula of $CH_2O$, empirical weight is =$1\times 12+2\times 1+1\times 16=30g$

To calculate the molecular formula.:

1. For compound a:

$n=\frac{\text{Molecular weight}}{\text{Equivalent weight}}=\frac{60.05}{30}=2$

The molecular formula will be=$2\times CH_2O=C_2H_4O_2$

2. For compound b:

$n=\frac{\text{Molecular weight}}{\text{Equivalent weight}}=\frac{180.16}{30}=6$

The molecular formula will be=$6\times CH_2O=C_6H_{12}O_6$

Answer 2

I believe that the choices for this question are:

C2H4O2, C4H8O4 
CH2O, C6H12O6 
C3H6O3, C6H12O6 
C2H4O2, C6H12O6 

 

The answer to this based on the molar masses given is:

C2H4O2, C6H12O6 

 

To prove calculate the molar mass:

C2H4O2 = 2*12 + 4*1 + 2*16 = 60

C6H12O6 = 6*12 + 12*1 + 6*16 = 180