Final answer:
To find the number of molecules in 777 grams of NH3, we convert grams to moles using the molar mass of NH3 and then use Avogadro's number to find the number of molecules. The number of hydrogen atoms can be calculated by considering that each NH3 molecule contains 3 hydrogen atoms.
Step-by-step explanation:
To find the number of molecules in 777 grams of NH3, we need to use the concept of Avogadro's number. Avogadro's number represents the number of particles (atoms or molecules) in one mole of a substance, which is approximately 6.022 x 10^23. First, we convert grams of NH3 to moles using the molar mass of NH3 (17.03 g/mol).
777 grams NH3 x (1 mole NH3 / 17.03 grams NH3) = 45.61 moles NH3
Next, we use Avogadro's number to find the number of molecules:
45.61 moles NH3 x (6.022 x 10^23 molecules NH3 / 1 mole NH3) = 2.75 x 10^25 molecules NH3
Since each NH3 molecule contains 3 hydrogen atoms, the number of hydrogen atoms can be calculated as:
2.75 x 10^25 molecules NH3 x (3 atoms H / 1 molecule NH3) = 8.25 x 10^25 atoms H