A gaseous hydrogen- and carbon-containing compound is decomposed and found to contain 82.66 % ca

A gaseous hydrogen- and carbon-containing compound is...

Key Concepts

Ideal Gas Law

The ideal gas law, expressed as PV = nRT, is used to relate the pressure, volume, temperature, and number of moles of a gas. In this context, it is used to calculate the number of moles in a given volume of gas under specified conditions. Once the number of moles is known, this information is key in determining the molar mass of the gas, which is crucial for finding the molecular formula of the compound.

Percent Composition

Percent composition refers to the percent by mass of each element within a compound. By using the percentages of elements, one can determine the ratio of the masses of each element present in a sample. This is the first step in establishing the empirical formula, which represents the simplest whole number ratio of the atoms in the compound.

Empirical Formula Determination

The empirical formula is derived by converting the mass percentages of the elements into moles, using their atomic masses, and then finding the simplest whole-number ratio among these mole values. This process allows us to establish the basic stoichiometric proportions of the elements in the compound without regard to the molecular mass.

Molecular Formula Determination

The molecular formula provides the actual number of atoms of each element in a molecule of the compound. It is determined by comparing the molar mass of the compound, which can be obtained experimentally, to the molar mass of the empirical formula. The molecular formula is an integer multiple of the empirical formula, and this multiple is found by dividing the experimental molar mass by the empirical formula mass.

Transcript

00:01 Solution for the given problem here here we have to find molecular formula by using the given data so here the given data is first we have elements here elements are here carbon and hydrogen element and next here is percentage of the given elements and next is number of gram atoms and fourth one is atomic ratio we have to find atomic ratio and finally we have to find here empirical formula so the given elements here carbon and percentage composition of carbon in a given compound is here 82 .66 gram of carbon and number of gram atoms here we have to divide molecular mass by given by molecular mass so here and is equal to given mass by molecular mass so here given mass is 82 .66 and molecular mass is here carbon 12 .0107 is equal to 6 .8822.

03:57 And next is atomic ratio.

04:02 Atomic ratio here we will divide all numbers by the smallest amount of moles.

04:08 So here first we will first we will consider hydrogen.

04:15 We will calculate here number of gram atoms for hydrogen then we will calculate atomic ratio so here for hydrogen hydrogen percentage composition is 17 .34 gram of hydrogen and number of gram atoms here given mass divided by molecular mass so given mass is 17 .34 divided by molecular mass of hydrogen is 1 .0079 is equal to we have 17 .204 moles of hydrogen.

05:12 And here is moles of carbon.

05:15 Now we will find atomic ratio.

05:19 And so here atomic ratio, here we will divide all numbers by the smallest amount of moles.

05:27 So the smallest amount of mall here is 6 .8822.

05:32 This is the smallest.

05:33 We will divide this number and 6 .8822 divided by smallest amount of mall is 6 .8822 is equal to 1.

05:52 And next is hydrogen.

05:55 We will divide given mass 17 .20.

06:00 4 divided by smallest amount of mall is 6 .882 is equal to we have 5 upon 2.

06:12 Now here to find empirical formula we will convert this fraction into whole number.

06:22 So by multiplying next we have is by multiplying multiply the atomic ratio of carbon hydrogen by whole number whole number in a day to get empirical formula empirical formula so here the empirical formula will be here two is whole number and one is the atomic ratio of carbon is equal to two carbon atom and next is two into five upon two is equal to five hydrogen so the empirical formula will be here c2h5.

07:59 And next we have to determine molar mass of the empirical formula formula c2h5.

08:34 So here we have 2 into molar mass of carbon...

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