How many liters of Argon gas are present in a 10.5 mole sample?

235.2 L ( if the sample is under S.T.P condition )

Explanation:

For any gas at S.T.P (0°c, 1 atm), 1 mole=22.4 L

Thus, for  10.5 mole of Ar, there are 10.5*22.4=235.2 L

in chemistry, a solution’s concentration is how much of a dissolvable substance, known as a solute, is mixed with another substance, called the solvent. the standard formula is c = m/v, where c is the concentration, m is the mass of the solute dissolved, and v is the total volume

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).