# Help

## Recommended Posts

5 dm3 of carbon monoxide, CO(g), and 2 dm3 of oxygen, O2(g), at the same temperature and pressure are mixed together. Assuming complete reaction according to the equation given, what is the maximum volume of carbon dioxide, CO2(g), in dm3, that can be formed?

2CO(g) + O2(g) → 2CO2(g)

The answer is 4, but I don't know how to get there, can someone please explain this. Am I supposed to change the dm3 to moles?
##### Share on other sites
• 2 weeks later...

You don't need to convert to moles. It is basically like fairly simple algebra equation. (There may be a faster way to do this; It's been a few years since I've done anything chemistry related.)

We know that 2CO(g) + O2(g) → 2CO2(g) which means it takes 2 CO and 1 O2 to make 2 CO2. We have 5 dm3 of CO(g), and 2 dm3 of O2(g) And we want to know much CO2(g), in dmthese will produce.

Since the units are all the same we don't need to convert anything.

So,

Step 1 - find the limiting reagent. The O2 can make 2 CO2 and the CO2 can make 2.5 CO2. So O2 is the limiting reagent.

Step 2 - multiply the reaction equation by the amount the limiting reagent can produce. 2(2CO(g) + 1O2(g) → 2CO2(g))

We get: 4CO(g) + 2O2(g) → 4CO2(g)

So, 4 dm3 CO2

Hopefully this make sense. If not hopefully someone else can explain it better 🙂

## Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.