How many moles are there in a 12.0 g sample of gas that occupies 19.2 L at STP?

Sure, here's how you can calculate the number of moles in a 12.0 g sample of gas that occupies 19.2 L at STP:

1. First, you need to know that at STP (Standard Temperature and Pressure), 1 mole of any gas occupies 22.4 L. This is known as the molar volume of a gas at STP.

2. Next, you can calculate the number of moles in 19.2 L of gas by using the formula:

   Number of moles = Volume of gas / Molar volume at STP

   Substituting the given values:

   Number of moles = 19.2 L / 22.4 L/mole = 0.857 moles

So, there are approximately 0.857 moles in a 19.2 L sample of gas at STP.