A 5.00 g of a certain Compound X, known to be made of carbon, hydrogen and perhaps oxygen, and to have a molecular molar mass of 78./gmol, is burned completely in excess oxygen, and the mass of the products carefully measured: product mass
carbon dioxide 16.93g
water 3.46g
Use this information to find the molecular formula of X.

C6H6

Explanation:

Step 1:

Data obtained from the question. This include the following:

Mass of the compound = 5g

Molar mass of the compound = 78g/mol

Mass of CO2 = 16.93g

Mass of H2O = 3.46g

Step 2:

Determination of the mass of carbon, hydrogen and oxygen present ij the compound. This can be obtained as follow:

Molar mass of CO2 = 12 + (2x16) = 44g/mol

Mass of C = 12/44 x 16.93 = 4.62g

Molar mass of H2O = (2x1) + 16 = 18g/mol

Mass of H = 2/18 x 3.46 = 0.38g

Mass of O = 5 – (4.62 + 0.38) = 0

Step 3:

Determination of the empirical formula of the compound.

C = 4.62g

H = 0.38g

Divide by their molar mass

C = 4.62/12 = 0.385

H = 0.38/1 = 0.38

Divide by the smallest

C = 0.385/0.38 = 1

H = 0.38/0.38 = 1

Therefore, the empirical formula of the compound is CH.

Step 4:

Determination of the molecular formula of the compound.

The molecular formula of a compound is simply a multiple of the empirical formula.

The molecular formula => [CH]n

[CH]n = 78

[12 + 1]n = 78

13n = 78

Divide both side by 13

n = 78/13

n = 6

The molecular formula => [CH]n

=> [CH]6

=> C6H6.

Therefore, the molecular formula of the compound is C6H6.

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.