The molecular formulas of the empirical ones of P₂O₅ and CH₂O are P₄O₁₀ and C₇H₁₄O₇, respectively, knowing that their molar masses are 310 and 200.18 g/mol, respectively.
We can calculate the molecular formula as follows:
[tex] MF = n*EF [/tex] (1)
Where:
To calculate the integer n, we need to use the following equation:
[tex] n = \frac{M}{M_{EF}} [/tex] (2)
Where:
The molar mass of the empirical formula of P₂O₅ is given by:
[tex]M_{EF} = 2A_{P} + 5A_{O}[/tex]
Where:
So, the molar mass of the empirical formula of P₂O₅ is:
[tex] M_{EF} = (2*30.974 + 5*15.999) g/mol = 141.943 g/mol [/tex]
Now, we can find the integer n (eq 2).
[tex] n = \frac{M}{M_{EF}} = \frac{310 \:g/mol}{141.943 \:g/mol} = 2 [/tex]
Finally, after multiplying the integer n by the number of atoms on the empirical formula of P₂O₅, we have (eq 1):
[tex]MF = n*EF = 2 \times P_{2}O_{5} = P_{(2 \times 2)}O_{(5 \times 2)} = P_{4}O_{10}[/tex]
Therefore, the molecular mass of P₂O₅ is P₄O₁₀.
We know:
To calculate the integer n and so the molecular mass of the molecule, we need to calculate the molar mass of the empirical formula of CH₂O.
[tex]M_{EF} = A_{C} + 2A_{H} + A_{O} = (12.011 + 2*1.008 + 15.999) g/mol = 30.026 \:g/mol[/tex]
Now, the integer n is equal to (eq 2):
[tex] n = \frac{M}{M_{EF}} = \frac{200.18 g/mol}{30.026 g/mol} \approx 7 [/tex]
Finally, the molecular formula of the molecule is (eq 1):
[tex]MF = n*EF = 7 \times CH_{2}O = C_{(1 \times 7)}H_{(2 \times 7)}O_{(1 \times 7)} = C_{7}H_{14}O_{7}[/tex]
Therefore, the molecular formula of CH₂O is C₇H₁₄O₇.
Learn more about molecular formula here:
I hope it helps you!
