Answer : The molar volume of the gas will be, 44.82 L
Solution :
Using ideal gas equation,

where,
n = number of moles of gas = 1 mole
P = pressure of the gas = 0.5 atm
T = temperature of the gas = 273 K
R = gas constant = 0.0821 Latm/moleK
V = volume of the gas.
Now put all the given values in the above equation, we get the molar volume of the gas.


Therefore, the molar volume of the gas will be, 44.82 L
POH=14-pH=14-2.5=11.5
pH=-log[H+]
2.5=-log [H+]
[H+]=10^-5/2
[OH-]=10^(14-5/2)=10^23/2
7.4x10^23 = molecules of silver nitrate sample
6.022x10^23 number of molecules per mole (Avogadro's number)
Divide molecules of AgNO3 by # of molecules per mol
7.4/6.022 = 1.229 mols AgNO3 (Sig Figs would put this at 1.3)
(I leave off the x10^23 because they both will divide out)
Use your periodic table to find the molar weight of silver nitrate.
107.868(Ag) + 14(N) + 3(16[O]) = 169.868g/mol AgNO3
Now multiply your moles of AgNO3 with your molar weight of AgNO3
1.229mol x 169.868g/mol = 208.767g AgNO3
6 is the fourth significant figures
if the number behind it is 5 or more then 5, you must add 1 to the number and ALL the number behind it will turn into 0
so that the answer is 42560