Answer:
mol times or devided by molar volume
From what there’s nothing there? :)
Answer:
the smallest mass of material that can sustain a chain reaction
Explanation:
Critical mass refers to the smallest possible mass of a fissionable material that can sustain a chain reaction
Relatively few hydrogen atoms
Answer: The pressure will be 18.05 atm.
Explanation: Expression for ideal gas equation is :

where,
P = Pressure of the gas = ? atm
V = Volume of the gas = 0.333L
n = Number of moles of gas = 0.250 moles
R = Universal gas constant = 
T = temperature of the gas = 20°C = (273 + 20)K = 293K
Putting values in above equation, we get:

P = 18.05 atm