Ahot air balloon is filled with 15 moles helium gas and 5 moles of nitrogen gas. what is the volume of the balloon at 1.01 atm and 300 k.

Answer is: volume of the balloon is 487.485 liters.

n = 15 mol + 5 mol.

n = 20 mol; amount of substance.  

p = 1.01 atm; pressure of the balloon.  

T = 300 K; temperature.  

R = 0.08206 L·atm/mol·K, universal gas constant.  

Ideal gas law: p·V = n·R·T.  

V = n · R · T ÷ p.

V = 20 mol · 0.08206 L·atm/mol·K · 300 K ÷ 1.01 atm.

V = 487.485 L; volume of the balloon.

i'm assuming that the correct answer is indeed the first one/ "a"..

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.