Answer:
Carbon
Step-by-step explanation:
To know this, let's write the ideal gas expression:
PV = nRT
As we are in STP, means that we have a pressure of 1 atm and 0 °C or 273.15 K. So, we have the volume which is 2 L, all we have to do is to calculate the moles of the substance, and then, the molecular weight with the given mass. The molecular weight that matches any of the option, would be the elemento that fullfill these conditions:
the moles (n):
n = PV/RT
n = 1 * 2 / (0.08206*273.15)
n = 0.089 moles
Now that we have the moles, let's calculate the molecular weight.
MM = m/n
MM = 1 / 0.089
MM = 11.24 g/mol
This molecular weight is very close to the molecular mass of the carbon (12 g/mol) . So the correct option is b, carbon.