Question

Calculate the molar mass of acetone?

Answer 1

Hint :We know that the concept of the formula mass and the molar mass calculation using the definition that sum of atomic mass of all the atoms in the formula unit gives formula mass and the quantity of the substance is the molar mass in grams.

Complete Step By Step Answer:
Let us now see the calculation of molar mass and formula mass according to their definitions. Formula mass is defined as ‘the sum of the atomic masses of all the atoms in the formula unit in an ionic crystal’. Molar mass of a substance is defined as the quantity of the substance which is equal to the molecular mass in grams. Molar mass is the mass of one mole of a given compound or substance. -We know that the number moles of a compound (n) are the ratio of the given mass of the compound to the molar mass of the compound. Relative molar mass is defined as the smallest mass unit of a compound with one twelfth of the mass of one \[carbon\text{ }\text{ }12\] atom. The molar mass of the compound can be calculated using the formula
\[Molar\text{ }mass=\dfrac{mass}{mole}g/mol\] and the chemical Formula of the Acetone is \[C{{H}_{3}}COC{{H}_{3}}\]
Now, let us calculate the mass of the compound
Mass of the Carbon, Hydrogen and Oxygen are \[C=12\text{ }g,~~~H=1\text{ }g\] and \[O=16\text{ }g\]
Molecular mass of the acetone \[=12+\left( 1\times 3 \right)+12+16+12+\left( 1\times 3 \right)\]
Molecular mass of the \[C{{H}_{3}}COC{{H}_{3~}}=12+3+12+16+12+3=36+6+16=58\text{ }g/mole\]

Note :
Remember that generally the mass of the substance or a compound is different from the molar mass of the substance. One mole of a molecule is equal to the Avogadro number of atoms or molecules present in the compound. Also don’t be confused with the words molar mass and molecular weight of the substance. Both are not the same. Mass of compound is the sum of atomic weight of each atom present in the given molecule but the molar mass means is the product of molecular weight and the number of moles of the given compound.