Acompound is 7.74% hydrogen and 92.26% carbon by mass. at 100°c a 0.6883 g sample of the gas occupies 250 ml when the pressure is 820 torr. what is the molecular formula for this compound?

The molecular formula for the compound is

Explanation:

We are given:

Percentage of C = 92.26 %

Percentage of H = 7.74 %

Let the mass of compound be 100 g. So, percentages given are taken as mass.

Mass of C = 92.26 g

Mass of H = 7.74 g

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 7.68 moles.

For Carbon =

For Hydrogen =

The ratio of C : H = 1 : 1

The empirical formula for the given compound is

To calculate the molecular mass, we use the equation given by ideal gas equation:

PV = nRT

Or,

where,

P = pressure of the gas = 820 torr

V = Volume of gas = 250 mL = 0.250 L  (Conversion factor:  1 L = 1000 mL )

m = mass of gas = 0.6883 g

M = Molar mass of gas = ?

R = Gas constant =

T = temperature of the gas =

Putting values in above equation, we get:

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 = 78.10 g/mol

Mass of empirical formula = 13 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 molecular formula for the compound is

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error

that's what i got you can count the number of atoms