In Carius method of estimation of halogen, \(0.15 \mathrm{~g}\) of \mathrm{\\{} 2 n ~ o r g a n i c ~ c o m p o u n d ~ g a v e ~ \(0.12 \mathrm{~g}\) of \(\mathrm{AgBr}\). What is the percentage of bromine in the compound? (a) \(68.08 \%\) (b) \(34.049\) (c) \(42,1 \%\) (d) \(50 \%\)

The molar mass of a substance is the weight of one mole of that substance, expressed in grams per mole (g/mol). The molar mass is numerically equal to the atomic or molecular mass of the substance when expressed in atomic mass units (amu). For example, the molar mass of water (H₂O) is approximately 18 g/mol because the molecular mass is roughly 18 amu.

Understanding molar mass is crucial when dealing with chemical reactions because it helps us determine how much of a substance reacts or is produced. To calculate the molar mass, you sum up the molar masses of all the atoms in the molecule. For instance, in the Carius method problem, the molar mass of silver bromide (AgBr) is determined by adding the molar masses of silver (Ag) and bromine (Br), which are approximately 107.9 g/mol and 79.9 g/mol, respectively. So, the molar mass of AgBr would be roughly 187.8 g/mol (107.9 g/mol + 79.9 g/mol).

Calculating the number of moles of a compound helps in quantifying the amount of substance involved in a chemical reaction. A mole is a unit of measurement that represents a quantity (6.022 x 10²³ particles) - known as Avogadro's number.

To calculate moles from mass, we use the formula: moles = mass / molar mass. Applied to our given exercise, we can calculate the moles of silver bromide (AgBr) by using the extracted mass of the AgBr produced and its molar mass. In this problem, we take the mass of AgBr (0.12 g) and divide it by its molar mass (187.8 g/mol), which gives us the moles of AgBr. This step is fundamental because it sets the stage for determining the amount of bromine in the compound, allowing us to assess its percentage composition.

Percentage composition is a measure of the relative amount of each element within a compound. It indicates the ratio of the mass of each element to the total mass of the compound, multiplied by 100%.

In the context of the Carius method problem, to find the percentage of bromine in the organic compound, we must first determine the mass of bromine present. After calculating the moles of AgBr, as previously discussed, we then deduce the mass of bromine since one mole of AgBr contains one mole of Br. By multiplying the moles of bromine by its atomic mass, we find the mass of bromine. Finally, we calculate the percentage by dividing the mass of bromine by the original mass of the organic compound and multiplying by 100%. This outcome is essential for understanding the composition of the compound and is integral to suitably characterizing its chemical structure.