We have the compound Ec3H3O5. I assume that the compound Ec is an unknown compound, but we are given the molar mass of the compound Ec.
The molar mass of the molecule will be equal to the sum of the masses of each element multiplied by the number of times that it is repeated in the molecule, to make it clearer we can make the following table:
The molar mass of the molecule will be equal to 146.39g/mol, therefore the moles in 28.87 grams will be:
[tex]\begin{gathered} \text{Mol }_{}Ec_3H_3O_5=GivengEc_3H_3O_5\times\frac{1molEc_3H_3O_5}{MolarMass,gEc_3H_3O_5} \\ \text{Mol}Ec_3H_3O_5=28.87gEc_3H_3O_5\times\frac{1molEc_3H_3O_5}{146.39gEc_3H_3O_5}=0.20molEc_3H_3O_5 \end{gathered}[/tex]In 28.87g of Ec3H3O5 there are 0.20molEc3H3O5
