Molar Volume of a Gas at STP

How was your winter break guys? Yeah, I miss it too. Oh well, all we can do now is slug through school and wait for spring break to come!! But we all love chemistry (!) so it will be okay. :)

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So last class we learned about STP, you're probably thinking "What in the name of monkeyballs is STP?!" Well I'll tell you what STP is, it stands for Standard Temperature & Pressure.

Here are some notes about what we learned last class:

• Gases expand when the temperature rises and contract (change volume) when cooled all due to changes in the temperature and pressure.
• We have a standard condition to compare volume of gasses called STP (Standard Temperature and Pressure).
• STP = 1 atmosphere of pressure and a temperature of 0°C or 273.15K
• At STP 1 mole of gas occupies 22.4L

Since we know that 1 mole ALWAYS occupies 22.4L at STP, we can create the conversion factors:
22.4L of gas               or             1 mole of gas
1 mole of gas                               22.4L of gas

This is VERY useful!! Make sure to add this into your mole map!


For example, calculate the volume occupied by 5.3g of carbonate at STP.
Step 1: Find the molar mass of carbonate (CO₃).
(1x12.0) + (3x16.0) = 60.0g
Step 2: Convert into moles.
5.3g x (1 mol / 60.0g) = 0.08833 moles
Step 3: Calculate the volume using the conversion factors.
(22.4L / 1 mole) x (0.08833 mole) = 1.9787L

∴Volume occupied by 5.3g of ammonia at STP is 2.0L

And voilà! Now you have learned all about STP and how to use it in an equation!
Hope this blog helps you guys and remember, quiz on Thursday so review your moles!

Love, Kimberly:)