Chemistry help needed!

Can someone explain to me how to solve this problem?

Ethylene burns in oxygen to form carbon dioxide and water vapour C2H4+3O2 ----> 2CO2 + 2H2O. How many litres of water can be formed if 1.25 litres of ethylene are burned?

Thanks!

Ahh Chemistry, How I love thee. Sadly I had to look up Ethylene, as we only used Ethene in the work I've done.

• You turn litres to moles.
• You then fit it into the equation and fill in the ratios.
• You then turn the moles of water into litres.

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Fantastic work

It is more than likely you are taking a chemistry class if asking this question, in which case you should be asking your teacher, not anonymous people on the internet. Also, it has been a long time since I've taken any sort of chemistry class, and I'm certainly no expert and could easily be incorrect. But density depends on the temperature and pressure, so you have to make an assumption if using liters.

The formula you provided shows a reaction in molar units. So to be using that information, we want to know our inputs in molar units. I asked Wolfram Alpha to convert liters of ethylene to moles (it didn't specify a temperature, so maybe room temperature would be assumed?). Don't use Wolfram Alpha if you are a student. If you don't know how to convert from mass to moles, I can tell you. For 1.25 liters of ethylene, I got 51.4 mol.

Now you can use that information in the formula since you have a mol value. The formula for a unit of ethylene is C2H4 so you have 1 mol of it on the left side. Water is H2O so you are producing 2 mols of water out of that one mol of ethylene according to the formula. 2 moles of water for each mol of ethylene. Since you have 51.4 mol of ethylene, you are producing 102.8 mol of water.

Since you want to know liters of water, then convert 102.8 mol of water to liters of water. Again don't use Wolfram Alpha like I am (and ask if you don't know how to convert), which says the result is 1.852 L. Then 1.852 L is your answer.

Again, I do not have any degree in Chemistry. I have done very little chemistry. Do not assume I am correct. Check with a professional.

Edit: Ahh, someone beat me to it. Looks like I was wrong. Or wolfram alpha was. Perhaps the other answerer knows how to get Woflram Alpha to know what the standard temperature and pressure is to use?

Thanks for all the help!