Question

What mass of nitrogen is needed to fill an 855 L tank at STP?

Answer 1

Answer:

It takes 1,068.76 grams of nitrogen to fill an 855 L tank at STP.

Explanation:

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C or 273.15 °K are used and are reference values for gases.

On the other side, the pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:  

P*V = n*R*T

where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas.

So, in this case:

• P= 1 atm
• V= 855 L
• n= ?
• R= 0.082 $\frac{atm*L}{mol*K}$
• T= 273.15 K

Replacing:

1 atm* 855 L= n* 0.082 $\frac{atm*L}{mol*K}$ * 273.15 K

Solving:

$n=\frac{1 atm* 855 L}{0.082\frac{atm*L}{mol*K} *273.15 K }$

n= 38.17 moles

Being the molar mass of nitrogen N2 equal to 28 g / mol, you can apply the following rule of three: if there are 28 grams in 1 mole, how much mass is there in 38.17 moles?

$mass=\frac{38.17 moles*28 grams}{1 mole}$

mass= 1,068.76 grams

It takes 1,068.76 grams of nitrogen to fill an 855 L tank at STP.