## How can we identify when to use the ideal gas law?

$PV=nRT$

Jenaye Brelland 2I
Posts: 95
Joined: Wed Sep 30, 2020 9:35 pm

### How can we identify when to use the ideal gas law?

How can we identify when to use the ideal gas law?

Saja Kamal 2L
Posts: 18
Joined: Thu Jul 25, 2019 12:16 am

### Re: How can we identify when to use the ideal gas law?

Hi!

I would say when the problem involves a gas and gives you the values for enough units like pressure, temperature, volume, or moles then you should implement the Ideal Gas Law!

Gwendolyn Hill 2F
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### Re: How can we identify when to use the ideal gas law?

As said above, if a problem gives you multiple elements of the ideal gas law and asks you to solve for one of them, like for pressure for example, then you would use the law. That is also especially true if you're not given a Kp; it means you can't do the ICE table right off the bat.

Audrey Han 3L
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Joined: Wed Sep 30, 2020 9:38 pm

### Re: How can we identify when to use the ideal gas law?

Also if you need the molarity of a solution but they've only given you pressure or temp, that's a good sign to use the ideal gas law.

darchen3G
Posts: 107
Joined: Wed Sep 30, 2020 9:39 pm

### Re: How can we identify when to use the ideal gas law?

You use it when you have all of these variables except one: pressure, volume, moles, temperature

Vivian_Le_1L
Posts: 40
Joined: Thu Dec 17, 2020 12:19 am

### Re: How can we identify when to use the ideal gas law?

Hi!

We can use the ideal gas law when we are given values for pressure, volume, concentration, and temp except for one. You can use it to solve for the missing variable. For example, in some of the problems we've done, we've used it to convert from concentration to pressure and vice versa.

Jaclyn Schwartz 1I
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Joined: Wed Sep 30, 2020 9:45 pm

### Re: How can we identify when to use the ideal gas law?

I recommend looking at the problem and see what units you are given, with any problem given for any test! And if the units happen to include pressure, temperature, volume, or moles, then the Ideal Gas Law will probably be the equation for you to use to find the missing variable!

DominicMalilay 1F
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Joined: Wed Sep 30, 2020 9:36 pm

### Re: How can we identify when to use the ideal gas law?

When the equation satisfies PV=nRT in all except one value like pressure, volume, etc, you can use the ideal gas law.

Armen_Isayan_2L
Posts: 101
Joined: Wed Sep 30, 2020 10:09 pm

### Re: How can we identify when to use the ideal gas law?

Hello! In order to know when to use the ideal gas law it is important to consider which units and variables have been provided in the question. For instance, if the units such as, temperature, volume or mole have been utilized then the ideal gas law is the best solution to find the missing variable

Charlotte Chen 3B
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Joined: Wed Nov 18, 2020 12:29 am

### Re: How can we identify when to use the ideal gas law?

Just to add on to the other answers, sometimes you won't directly get given all the variables e.g. you may be given mass instead of mols, but as long as there is sufficient information provided you should be able to calculate the necessary values to complete the expression (in this case you would divide mass by the molar mass to find the no. of mols)

Sarah Salam 1J
Posts: 55
Joined: Wed Sep 30, 2020 9:31 pm

### Re: How can we identify when to use the ideal gas law?

You'll have to look at the equation PV=nRT and see if the question is asking you to solve for one of these variables using what you are given. That would mean you are given or can solve for the rest of the variables.

Ellison Gonzales 1H
Posts: 99
Joined: Wed Sep 30, 2020 10:00 pm

### Re: How can we identify when to use the ideal gas law?

Is the unit for partial pressure in the ideal gas law always bar? Or bar and atm?