Answer:
2.0 atm is the difference between the ideal pressure and the real pressure.
Explanation:
If 1.00 mole of argon is placed in a 0.500-L container at 27.0 °C
Moles of argon = n = 1.00 mol
Volume of the container,V = 0.500 L
Ideal pressure of the gas = P
Temperature of the gas,T = 27 °C = 300.15 K[/tex]
Using ideal gas equation:


Vander wall's of equation of gases:
The real pressure of the gas= 
For argon:
b=0.03219 L/mol.



Difference :
2.0 atm is the difference between the ideal pressure and the real pressure.
Radioactivity or radioactive decay is the process that occurs when unstable isotopes or atoms release energy by emitting radiations such as ,gamma radiations, alpha radiations and beta radiations to attain stability. Therefore, in this case decay is likely to occur when a given atom has two many neutrons in its nucleus in order to attain stability.
The number of atoms in one mole of any substance is measured by Avogadro's number. The value of Avogadro's number is 6.023 x 10 ^23. It is named after scientist Avogadro who proposed this number. 12 grams of carbon-12 represents 1 mole of carbon-12. For this reason, the number of atoms present in 1 mole of any substance is 6.023 x 10 ^23. Therefore, the number of atoms present in 1 mole carbon-12 is 6.023 x 10^23.
(Answer) This unit is the number of atoms in 12 grams of carbon-12 and known as Avogadro's number.