Question

У 2грамах воднню скільки молекул і скільки атомів​

Answer 1

In 2 g H₂ there are 6,023.10²³ molecules H₂ and 2 x 6,023.10²³ atoms H

Further explanation

The mole is the number of particles contained in a substance

1 mol = 6.02.10²³

Moles can also be determined from the amount of substance mass and its molar mass

 

The question is :

in 2 grams of hydrogen how many molecules and how many atoms

• mol of Hydrogen - H₂

MW H₂ = 2.01568 u  (2 atoms of H)

MW H = 1.00784 u

$\tt mol=\dfrac{m}{MW}\\\\mol=\dfrac{2~g}{2.01568 u}=0.992$

• number of molecules

$\tt 0.992\times 6.02\times 10^{23}=5.97\times 10^{23}$

• mol of H

$\tt mol=\dfrac{2}{1.00784}= 1.984$

• number of atoms

$\tt 1.984\times 6.02\times 10^{23}=11.94\times 10^{23}$

Or a simply way :

1 g of H atoms = 1 mol of H  (MW H = 1 g/mol)

2 g of H atoms (in 2 gr H₂) = 2 moles of H  

2 g of H₂ molecules = 1 mole of H₂  (MW H₂=2 g/mol)

so in 2 g H₂ there are 6,023.10²³ molecules H₂ and 2 x 6,023.10²³ atoms H