Question: how many molecules are present in 5.6 litres of oxygen at ntp?
Answer: One mole of any gas occupies 22.4L of volume at NTP or STP and one mole of a gas contains Avogadro Number of molecules at NTP ie 6.022×10raised to 23. Therefore no. of molecules in 5.6 L of oxygen will be 6.022×10 raised to 23×5.6 ÷22.4=1.5055×10 raised to 23.