To determine the number of molecules in 26.2 grams of NH3 (ammonia), we need to use the following steps:
1. Calculate the molar mass of NH3:
The atomic mass of nitrogen (N) is 14.01 g/mol
The atomic mass of hydrogen (H) is 1.01 g/mol
NH3 has one nitrogen atom and three hydrogen atoms, so the molar mass of NH3 is:
M(NH3) = 14.01 g/mol + 3(1.01 g/mol) = 17.03 g/mol
2. Calculate the number of moles of NH3:
We can use the formula: moles = mass / molar mass
moles(NH3) = 26.2 g / 17.03 g/mol = 1.54 mol
3. Calculate the number of molecules of NH3:
Avogadro's number tells us that there are 6.022 x 10^23 molecules in one mole of a substance
Therefore, the number of molecules in 1.54 moles of NH3 is:
molecules(NH3) = 1.54 mol x 6.022 x 10^23 molecules/mol = 9.27 x 10^23 molecules
Therefore, there are 9.27 x 10^23 molecules in 26.2 grams of NH3.