How many grams of CO2 gas occupy 18.7L at STP? Be sure your answer has the correct number of significant figures.

To solve this problem, we need to use the molar volume of a gas at STP (Standard Temperature and Pressure), which is 22.4 L/mol.

1. First, we need to find out how many moles of CO2 are in 18.7L. We can do this by dividing the volume of CO2 by the molar volume at STP:

   Moles of CO2 = Volume of CO2 / Molar volume at STP Moles of CO2 = 18.7L / 22.4L/mol = 0.835 moles

2. Next, we need to convert moles of CO2 to grams. We can do this by multiplying the number of moles by the molar mass of CO2 (which is approximately 44.01 g/mol):

   Mass of CO2 = Moles of CO2 * Molar mass of CO2 Mass of CO2 = 0.835 moles * 44.01 g/mol = 36.7 g

So, 18.7L of CO2 gas at STP is approximately 36.7 grams. This answer has three significant figures, as the number with the least significant figures that we used in our calculations was the volume of CO2 (18.7L), which has three significant figures.