You have to use the equation PV=nRT.
P=pressure (in this case 1.89x10^3 kPa which equals 18.35677 atm)
1V=volume (in this case 685L)
n=moles (in this case the unknown)
R=gas constant (0.08206 (L atm)/(mol K))
T=temperature (in this case 621 K)
with the given information you can rewrite the ideal gas law equation as n=PV/RT.
n=(18.35677atm x 685L)/(0.08206atmL/molK x 621K)
n=246.8 moles
Answer: El HEXAHIDRATO DE SULFATO DE NÍQUEL es incompatible con ácidos fuertes, azufre, Ni (NO3) 2, madera y otros combustibles. (NTP, 1992) A temperatura elevada sufre una reacción violenta con aluminio o magnesio en polvo. Cuando se calienta hasta la descomposición emite humos muy tóxicos de óxidos de azufre
Explanation:
Answer to his question is C
Since Na has a 1+ charge and O has a -2 charge, by reversing the charges and placing them as subscripts for the other atoms the formula is Na2O1 or simply Na2O.
The answer is to test a piece of untreated and treated under same conditions!