Answer:
4.95×10^22 atoms of hydrogen.
Step-by-step explanation:
Now, we must remember that the number of elementary entities in one mole of a substance (atoms, molecules, ions,etc) is given by the Avogadro's number. Avogadro's number is numerically equal to 6.02×10^23.
We must first find the number of moles of hydrazine corresponding to 2.65 g
We find that from;
Number of moles= mass of hydrazine given/ molar mass of hydrazine
Molar mass of hydrazine= 32.0452 g/mol
Number of moles of hydrazine= 2.65/32.0452 g/mol= 0.0823 moles
If 1 mole of hydrazine contains 6.02×10^23 hydrogen atoms
0.0823 moles of hydrazine will contain 0.0823 moles × 6.02×10^23 = 4.95×10^22 atoms of hydrogen.