You are Here: Home >< Maths

# ☹ The Ideal Gas Equation - Rearranging Formulae ☹ watch

1. Hi all,

Admittedly, I have never understood how to rearrange formulae. I've tried to teach myself how but to no avail so now I've resorted to asking here. . .

Ideal Gas Equation: pV = nRT

V = nRT
-------p

P = nRT
-------V

n = pV
-----RT

R = pV
-----nT

T = pV
-----nR

But how has this been done?
2. (Original post by AshEntropy)
Hi all,

Admittedly, I have never understood how to rearrange formulae. I've tried to teach myself how but to no avail so now I've resorted to asking here. . .

Ideal Gas Equation: pV = nRT

V = nRT
-------p

P = nRT
-------V

n = pV
-----RT

R = pV
-----nT

T = pV
-----nR

But how has this been done?
Its just dividing/multiplying by the variables to isolate the one you want. To obtain T, for example, multiply by p then divide by nR.
3. (Original post by hezzlington)
Its just dividing/multiplying by the variables to isolate the one you want. To obtain T, for example, multiply by p then divide by nR.
But how do you know exactly what to multiple and divide, that's what I don't understand. . . Isn't there an easier way of thinking about it, like carrying letters over the = sign or something?
4. (Original post by AshEntropy)
But how do you know exactly what to multiple and divide, that's what I don't understand. . . Isn't there an easier way of thinking about it, like carrying letters over the = sign or something?
By the way, learn how to use the built in latex function for writing out mathematical equations, I was on my phone and I was really confused at what the dashed lines meant.

Take

Let's say you want to know what the Temperature (T) is.

You have the two components on the right hand side of the equation:

which you want to 'move to the other side of the equation to isolate . To do this, you divide by .

This then puts . 'underneath' the component. This is called the denominator of the fraction, giving:

5. (Original post by hezzlington)
By the way, learn how to use the built in latex function for writing out mathematical equations, I was on my phone and I was really confused at what the dashed lines meant.

Take

Let's say you want to know what the Temperature (T) is.

You have the two components on the right hand side of the equation:

which you want to 'move to the other side of the equation to isolate . To do this, you divide by .

This then puts . 'underneath' the component. This is called the denominator of the fraction, giving:

Sorry about that, next time I'll use Latex

And thank you very much! Now it makes a whole lot more sense
6. (Original post by AshEntropy)
Sorry about that, next time I'll use Latex

And thank you very much! Now it makes a whole lot more sense
to get nR back over to the other side after dividing, you just use the inverse operation, which would be multiplication.

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: January 19, 2017
Today on TSR

### Summer Bucket List is Back!

Start yours and you could win £150!

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams