Question

Calculate the mass of 0.72 gram molecules of $C{{O}_{2}}$ .

Answer 1

Hint:
Before talking about the answer, you should know the basic formula to calculate the number of moles, which is equal to weight per molar mass of the compound. So, to calculate the mass of the compound, you will need to multiply weight with the number of moles.

Formula used:
$n=\dfrac{W}{m}$
where, $n$ is the number of moles, $W$ is the weight of the compound and $m$ is the molar mass of the compound.

Complete answer:
Here, it is given that the weight of molecules of $C{{O}_{2}}$ is $0.72g$ .
When a calculation of formula mass is done by the addition of atomic masses of its component and express it into grams, then it is known as gram formula mass.
Molar mass of $C{{O}_{2}}$ is: $12+16\times 2=44g\,mo{{l}^{-1}}$
In this question, we have to apply mole concept and that is,
 $n=\dfrac{W}{m}$
where, $n$ is the number of moles, $W$ is the weight of the compound and $m$ is the molar mass of the compound.
Now, we will substitute the values in the above formula, the weight of $C{{O}_{2}}$ is,
 $n=\dfrac{W}{m}$
 $\Rightarrow W=n\times m$
 $\Rightarrow W=0.72\times 44\Rightarrow 31.68g$
Therefore, the mass of $C{{O}_{2}}$ is $31.68g$ .

Additional information:
Moles is defined as a scientific unit which is used to measure large quantities of atoms and molecules. It is defined as the amount of substance present in a sample.
$1\,mole=6.022\times {{10}^{23}}particles$
This is also called Avogadro's number $({{N}_{A}})$ .
Molar mass is defined as the addition of atomic mass of atoms, combined in a molecule. Here, the molar mass of $C{{O}_{2}}$ is $44g$ .
Moles are defined as the weight of the compound per molar mass of the compound.
Formula mass is different from molecular mass. In formula mass, there is an addition of atomic masses of ions present in an ionic compound, whereas molecular mass is the addition of atomic masses of the atoms in a molecule.

Note: The molar mass is calculated in $g\,mo{{l}^{-1}}$ .
Mole is used to calculate the small entities like atoms, molecules and ions. Relative molar mass is defined as the one twelfth of the mass of the carbon.