### How does Avogadro's number relate to atomic mass?

The atomic mass unit (amu or simply u) is the 1 / 12 of the mass of a X 12 X 2 2 12 C atom. Avogadro's number (N A = 6.022 × 10 23) is the number of atoms contained in 12 g of X 12 X 2 2 12 C. The relation between them has to do with relative atomic mass (A r), which is basically the number of atomic mass units an atom is equal to. Example Exercise 9.1 Atomic Mass and Avogadro’s Number. The atomic mass of each element is listed below the symbol of the element in the periodic table: Cu = 63.55 amu, Hg = 200.59 amu, S = 32.07 amu, and He = 4.00 amu. The mass of Avogadro’s number of atoms is the atomic mass expressed in grams. Therefore, 6.02. Click here👆to get an answer to your question ️ The molecular mass of CO2 is 44 amu and Avogadro's number is 6.02 × 10^23. Therefore, the mass of one molecule of CO2 is. As, 1 amu = 1/12 of mass of one C-12 atom The value of amu doesn't depend upon Avogadro number. So atomic mass of oxygen will still be same as 16 amu, which simply means that one atom of O is 16 times heavier than “ 1/12 of mass of one C-12 atom” Edit-1.

The atomic mass tells you have many grams there are per mole of something.

## = 1 Gram

1 mole contains approximately $6.02 \cdot {10}^{23}$ atoms or molecules (depending on what is being talked abotu, whether number of water molecules, atoms of magnesium or total atoms in $' N a C l '$)

So for example, water has a mass of around $18 g$$m o {l}^{-} 1$, this means that 18g of water contains $6.02 \cdot {10}^{23}$ water molecules, but $1.806 \cdot {10}^{24}$ atoms (three atoms per water molecule).

Anther example, magnesium has a mass of around $24.3 g$$m o {l}^{-} 1$, and 10g contains $\frac{10}{24.3} \approx 0.412 m o l$ of Mg. $0.412 \left(6.02 \cdot {10}^{23}\right) \approx 2.48 \cdot {10}^{23}$ atoms ## Related questions

Moles and Avogadro’s number are big! And they come across as overwhelming. But YOU can master them!

This video covers the definition of Moles, with an illustration showing the logic of moles in general chemistry. You’ll also see how to easily and quickly convert from and to them on the MCAT.

You’ll see conversions including atoms, AMU, grams, and moles. Let’s knock this out on your MCAT Content Category List!