Question

At STP a 22.4 liter sample of NH3(g) contains the same number of molecules as

Answer 1

A 22.4-liter sample of NH3(g) at STP contains one mole of molecules. This same number of molecules would also be found in any other gas that occupies 22.4 liters at STP.

Step-by-step explanation:

The student's question pertains to the concept of Avogadro's law which states that equal volumes of gases, at the same temperature and pressure, contain the same number of molecules. Specifically, the question involves the molar volume of a gas at Standard Temperature and Pressure (STP). At STP, one mole of any gas occupies 22.4 liters. Therefore, a 22.4-liter sample of NH3(g) contains one mole of NH3, which is Avogadro's number (6.022 x 1023) of molecules.

Applying this to other gases at STP, any other gas that occupies a volume of 22.4 liters will also contain one mole and the same number of molecules as the NH3 sample. For example, 22.4 liters of H2 gas at STP also contains Avogadro's number of molecules, equal to the number in the NH3 sample.

Answer 2

At STP a 22.4 liter sample of ammonia contains the same number of molecules as one mole.

At standard temperature and pressure 1 mol of gas occupied 22.4 liters:
V(NH₃) = 22.4 L; volume of water.
Vm = 22.4 L/mol; molar volume at STP.
n(NH₃) = V ÷ Vm.
n(NH₃) = 22.4 L ÷ 22.4 L/mol.
n(NH₃) = 1 mol; amount of substance.
N(NH₃) = n(NH₃) · Na.
N(NH₃) = 1 mol · 6.022·10²³ 1/mol.
N(NH₃) = 6.022·10²³; number of molecules.
Na - Avogadro number or constant.