How many molecules are contained in 25.0 g H2? Solution: (A.wt H= 1.008 g/mole)
To find the number of molecules in 25.0 g of H2, we need to convert grams to moles and then use Avogadro's number to convert moles to molecules.
First, let's calculate the number of moles of H2 in 25.0 g:
Number of moles = mass / molar mass
Number of moles = 25.0 g / (1.008 g/mol)
Number of moles = 24.8 mol
Next, we use Avogadro's number, which states that one mole of any substance contains 6.022 x 10^23 molecules.
Number of molecules = Number of moles × Avogadro's number
Number of molecules = 24.8 mol × (6.022 x 10^23 molecules/mol)
Number of molecules = 1.491 x 10^25 molecules
Therefore, there are approximately 1.491 x 10^25 molecules in 25.0 g of H2.