A gaseous compound containing hydrogen and carbon is...

A gaseous compound containing hydrogen and carbon is decomposed and found to contain $82.66 \%$ carbon and $17.34 \%$ hydrogen by mass. The mass of $158 \mathrm{~mL}$ of the gas, measured at $556 \mathrm{~mm} \mathrm{Hg}$ and $25^{\circ} \mathrm{C},$ is $0.275 \mathrm{~g} .$ What is the molecular formula of the compound?

Key Concepts

Percent Composition

This concept involves expressing the mass of each element present in a compound as a percentage of the total mass. It is used to determine the relative amounts of each element, which helps in arriving at the empirical formula by converting these percentages to a mole ratio for each element.

Empirical Formula

The empirical formula of a compound represents the simplest whole-number ratio of the elements present. It is derived by converting the percent composition of each element into moles and then simplifying the ratios. This formula is fundamental for understanding the basic composition of the compound before determining the full molecular formula.

Ideal Gas Law

The Ideal Gas Law is an equation of state that relates the pressure, volume, temperature, and number of moles of a gas (PV = nRT). It is essential in gas stoichiometry for converting between these quantities, thereby allowing the calculation of the amount (in moles) of a gaseous compound from experimental data.

Molar Mass Determination

Molar mass determination involves finding the mass of one mole of a compound. When combined with measurements from the Ideal Gas Law, the experimentally determined mass of a gas sample can be divided by the number of moles calculated, yielding the molar mass. This value is critical for linking the empirical formula to the molecular formula.

Molecular Formula

The molecular formula provides the actual number of atoms of each element in a molecule, which may be a multiple of the empirical formula. Once the molar mass is known, the ratio of the molar mass to the empirical formula mass gives a multiplication factor that, when applied to the empirical formula, results in the molecular formula. This final step completes the determination of the compound's precise molecular composition.

Transcript

0:00 Hi everyone.

00:01 So in this question a gase compound containing hydrogen and carbon is decomposed and found to contain 82 .66 percent carbon and 17 .34 % hydrogen by mass.

00:13 The mass of 158 m l of gas measured at 556 millimeter mercury and at 25 degrees celsius is 0 .275 gram.

00:26 What is the molecule formula of the compound? so given data, percentage carbon that is equal to 82 .66%.

00:49 Then percentage hydrogen that is equal to 17 .34%.

00:59 Then volume 158 ml that is equal to 158 upon 1000 that is equal to 158.

01:16 0158 liter, then pressure 556 millimeter of a g that is equal to 556 upon 760 that is equal to 536 atmosphere, then temperature, then temperature, 25 degrees celsius that is equal to 25 plus 273 nothing but 298 kelvin then w point 275 gram molecular formula question mark so you know a part that is element the next percentage then next atomic ratio then simplest atomic ratio then whole numbers, whole numbers, atomic ratio is nothing but number of moles and simplest atomic ratio is nothing simplest number of moles.

03:14 Now element first one is carbon.

03:17 Then second one is hydrogen.

03:22 Percentage of carbon they have given 82 .16 and this is 17.

03:28 34 then atomic ratio of carbon 82 .66 divided by 12 that is equal to 6 .883 then atomic ratio of hydrogen that is 17 .34 upon 1 it is 17 .34 so atomic ratio of carbon is 1 and that of hydrogen is 2 .52.

04:08 So whole number that is you have to multiply this by 2 and that is equal to 2 and this is equal to 5 .0 4 and that is equal to 5...

Please give Ace some feedback