Question

If the avogadro number $N_A$ is changed from $6.022\times {10}^{23}$ to $6.022\times {10}^{20}mo{l}^{-1}$ this would change:
A. the ratio of chemical species to each other in a balanced equation
B. the ratio of elements to each other in a compound
C. the mass in units of grams
D. the mass of one mole of carbons

Answer 1

Hint: We simply know that molar mass is the weight of the substance multiplied by the number of atoms and every mole or gram equivalent contains an equal number of atoms that is $6.022\times {10}^{23}$.

Complete step by step solution:
We know that one atomic mass unit is defined as exactly 1/12th mass of an atom of carbon-12. We know experimentally that the mass of an atom carbon 12 is $1.992\times {10}^{-23}$ g. The mass of another type of atom in grams can be expressed in atomic mass unit b using this relation as a conversion factor. It follows that the number of atoms in exactly 12 gm of carbon-12 is ${\displaystyle \frac{12}{1.9926\times {10}^{-23}}}=6.023\times {10}^{23}$
This relationship of number of objects to the atom is also true for ions or molecules.
Hence as asked in the question if the avogadro's number is changed then the mass of one mole of carbon will change from 12g to 12mg.

Therefore the correct option is D.

Though all other ratios and mass in units of grams remain the same. This situation is hypothetical as the number is a constant.

Note:
Every mole or gram equivalent has the same number of atoms defined as Avogadro’s number. From Avogadro’s law it is known that equal volumes of all gases contain equal numbers of molecules under similar conditions. Now since one mole of molecules of all gases contain the same number ($6.022\times {10}^{23}$ ) of molecules, therefore they occupy the same volume under similar pressure and temperature. The mass of one mole of atoms is exactly equal to the atomic mass in grams of that element.