A 125 ml sample of gas is at STP how many moles of gas are in the sample

5.58*10⁻³ moles of gas are in the sample.

Explanation:

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

Being 1000 mL equivalent to 1 L, then 125 mL is equal to 0.125 L. Then you can apply the following rule of three: if by STP conditions 22.4 L are occupied by 1 mole, 0.125 L are occupied by how many moles?

aomunt of moles= 5.58*10⁻³ moles

5.58*10⁻³ moles of gas are in the sample.