Question

Given ; 4.16g of carbon and 0.39g of hydrogen. The atomic weight of carbon is 12.011g/mol and the atomic weight of hydrogen is 1.008g/mol. Use this knowledge to calculate the molecular formula for benzene, what is the chemical formula for benzene????

Answer 1

There is not enough information to determine the molecular formula, but the empirical formula is `"CH"`.

Explanation:

The empirical formula is the simplest whole number molar ratio of the elements in the compound.

We must convert the masses of `"C"`and `"H"` to moles and then find the ratio.

`"Moles of C" = 4.16 color(red)(cancel(color(black)("g C"))) × "1 mol C"/(12.01 color(red)(cancel(color(black)("g C")))) = "0.3464 mol C"`

`"Moles of H" = 0.39 color(red)(cancel(color(black)("g H"))) × "1 mol H"/(1.008 color(red)(cancel(color(black)("g Cl")))) = "0.387 mol H"`

From this point on, I like to summarize the calculations in a table.

`bbul("Element"color(white)(m) "Mass/g"color(white)(m) "Moles"color(white)(m) "Ratio"color(white)(m)"Integers")`
`color(white)(mm)"C" color(white)(XXXm)4.16 color(white)(Xmll)0.3464 color(white)(Xm)1color(white)(mmmmll)1`
`color(white)(mm)"H" color(white)(XXXm)0.39 color(white)(mmll)0.387 color(white)(Xml)1.11 color(white)(mmml)1`

The molar ratio is `"C:H = 1:1"`.

The empirical formula is `"CH"`.

There is not enough information to determine the molecular formula.