Explain Why?

(a) "The number of atoms in a certain volume of hydrogen is twice the number of atoms in the same volume of helium at the same temperature and pressure."

(b) "When stating the volume of a gas, the pressure and temperature should also be given."

(c) Inflating a balloon seems to violate Boyle's law.

(a) Avogadro's Law states that "equal volumes of all gases under similar conditions of temperature and pressure contain the same number of molecules."

Considering equal volumes of hydrogen and helium,
volume of hydrogen gas = volume of helium gas

According to Avogadro's Law:
n molecules of hydrogen = n molecules of helium gas

i.e., nH₂ = nHe

1 molecule of hydrogen has 2 atoms of hydrogen and 1 molecule of helium has 1 atom of helium

∴ 2H = He

∴ atoms in hydrogen are double the atoms of helium.

(b) Since, the volume of a gas changes remarkably with change in temperature and pressure, it becomes necessary to choose standard values of temperature and pressure to which gas volumes can be referred.

(c) Boyle's law states that the volume of a dry gas is inversely proportional to its pressure at a constant temperature. When we inflate a balloon, the volume and pressure of the air increase simultaneously, seemingly violating Boyle's law. However, this is not the case because according to the law, the mass of the gas should remain constant. In the balloon scenario, as more air is blown into the balloon, the mass of the gas increases, ensuring Boyle's law is not violated.