A) combustion analysis of toluene, a common organic solvent, gives 5.86 mg of co2 and 1.37 mg of h2o. if the compound contains only carbon and hydrogen, what is its empirical formula?

b) menthol, the substance we can smell in mentholated cough drops, is composed of c, h, and o. a 0.1005-g sample of menthol is combusted, producing 0.2829 g of co2 and 0.1159 g of h2o. what is the empirical formula for menthol? if menthol has a molar mass of 156 g> mol, what is its molecular formula?

For a: The empirical formula for the given compound is

For b: The empirical and molecular formula for the given organic compound are

Explanation:

The chemical equation for the combustion of hydrocarbon follows:

where, 'x', and 'y' are the subscripts of Carbon and hydrogen respectively.

We are given:

Conversion factor used:  1 g = 1000 mg

Mass of

Mass of

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in  of carbon dioxide, of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in of water, of hydrogen will be contained.

To formulate the empirical formula, we need to follow some steps:

Moles of Carbon =

Moles of Hydrogen =

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is moles.

For Carbon =

For Hydrogen =

The ratio of C : H = 1 : 1

Hence, the empirical formula for the given compound is

The chemical equation for the combustion of menthol follows:

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of  = 0.2829 g

Mass of = 0.1159 g

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44g of carbon dioxide, 12 g of carbon is contained.

So, in 0.2829  g of carbon dioxide, of carbon will be contained.

For calculating the mass of hydrogen:

In 18g of water, 2 g of hydrogen is contained.

So, in 0.1159 g of water, of hydrogen will be contained.

Mass of oxygen in the compound = (0.1005) - (0.077 + 0.013) = 0.105 g

To formulate the empirical formula, we need to follow some steps:

Moles of Carbon =

Moles of Hydrogen =

Moles of Oxygen =

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.00065 moles.

For Carbon =

For Hydrogen =

For Oxygen =

The ratio of C : H : O = 10 : 20 : 1

The empirical formula for the given compound is

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is:

We are given:

Mass of molecular formula = 156 g/mol

Mass of empirical formula = 156 g/mol

Putting values in above equation, we get:

Multiplying this valency by the subscript of every element of empirical formula, we get:

Hence, the empirical and molecular formula for the given organic compound are

i think it is true since you can test the answer and can use observations to complete it.