Converting gram to atom or converting atom to gram is an basic and essential process to solve difficult calculations in chemistry. The conversion requires Avogadro's number, mole of substance and atomic weight. Formula for conversion of gram to atoms are given below.

**Formula to convert grams to moles :**moles = $\frac{atoms}{Avogadro's \ number}$

**Formula to convert moles to grams :**grams = moles $\times$ atomic mass

**Step 1 :**Make a note of the values given in the question.

**Step 2 :**According to the question, substitute the values and find the value accordingly.

moles = $\frac{atoms}{Avogadro's \ number}$

grams = moles $\times$ atomic mass

Given below are some of the problems which are solved step by step based on conversion of grams to atoms.

### Solved Examples

**Question 1:**Determine how many atoms of uranium are there in 25 gram of uranium?

**Solution:**

25g of U $\times$ $\frac{1 mole}{238g}$ = 0.11 moles of U

0.11 moles of U $\times$ $\frac{6.02 \times 10^{23} atoms}{mole}$ = 6.6 $\times$ 10$^{22}$ atoms of U.

**Question 2:**Determine how many moles of N$_{2}$O$_{3}$ are there in 4.66 X 1027 molecules of the material.

**Solution:**

4.66 $\times$ 10$^{27}$ moles $\times$ $\frac{1 mole}{6.02 \times 10^{23} molecules}$ = 7740 moles