Question

The molar mass of $C{O_2}$ is:

Answer 1

Molecular weight of the substance: It is defined as the sum of the molecular masses of all elements present in the substance.
Molecular formula: The molecular composition in the compound is known as molecular formula. For example: the molecule of water is ${H_2}O$ i.e. two atoms of hydrogen with oxygen.

Complete step by step solution:
First of all let us read about molecular formulas.
Molecular mass of an element: It is the atomic mass of an element.
Molecular weight of the substance: It is defined as the sum of the molecular masses of all elements present in the substance.
Number of moles: It is defined as the ratio of mass of the substance to the molecular mass of the substance.
Molecular formula: The molecular composition in the compound is known as molecular formula. For example: the molecule of water is ${H_2}O$ i.e. two atoms of hydrogen with oxygen.
Empirical formula: The molecular composition in the compound in simplest ratio is known as empirical formula. For example: the molecular formula of glucose is ${C_6}{H_{12}}{O_6}$ and its empirical formula is $C{H_2}O$ .
Now here we are given with the molecular formula of the compound i.e. carbon dioxide as $C{O_2}$ .
Now we already know that the molecular mass of carbon is $12$ and molecular mass of oxygen is $16$ . In this compound there is one atom of carbon and two atoms of oxygen are present. So the molecular mass of the compound will be $12 + 2 \times 16 = 44$ . Hence the molecular mass of carbon dioxide is $44u$ . $u$ is used for the unit of molecular mass.

Note:
Formula mass: It is defined as the sum of the atomic weights of all the atoms present in the compound. And if the compound is covalent in nature then the formula mass is known as molecular mass and if we are calculating mass of one mole of substance then it is known as molar mass.