Respuesta :
In this case we are given the percentage of each element in a sample, and we know that the molecular mass is 250 amu.
The amu unit is defined as:
1/12 of the mass of an unbound neutral atom of carbon-12.
And 1 mol of uma equals 1g.
So in this case knowing that 1 molecules has a weight of 250 uma, we can calculate the molar mass (g/mol), which is 250g/mol.
Now, we start in step 1.
Assuming that we have 100g of the substance, using the percentage given we calculate the mass (mx) of each element using the following formula:
[tex]m_x=(percentage_x).100g[/tex][tex]\begin{gathered} m_C=48g \\ m_H=4g \\ m_N=22.4g \\ m_S=12.8g \\ m_O=12.8g \end{gathered}[/tex]Step 2
To convert the number of grams of each element into moles we use the molar mass (M) of each of them, this information we obtain from the periodic table:
[tex]\begin{gathered} M_C=12.01g/mol \\ M_H=1.0g/mol \\ M_N=14.0g/mol \\ M_S=32.06g/mol \\ M_O=16.g/mol \end{gathered}[/tex]So we calculate the moles (n) as follows:
[tex]n=\frac{m}{M}[/tex][tex]\begin{gathered} n_C=4mol \\ n_H=4mol \\ n_N=1.6mol \\ n_S=0.35mol \\ n_O=0.8mol \end{gathered}[/tex]Step 3
We divide the number of moles of each element by the smallest number obtained:
[tex]\begin{gathered} C=\frac{4mol}{0.35mol}=11.43 \\ H=\frac{4mol}{0.35mol}=11.43 \\ N=\frac{1.6mol}{0.35mol}=4.57 \\ S=\frac{0.35mol}{0.35mol}=1 \\ O=\frac{0.8mol}{0.35mol}=2.28 \end{gathered}[/tex]Steps 4 and 5
To calculate the empirical formula, we use
