R Constant

[Leslie Almaraz 4G]

How do you know which variation of the R constant to use?

[Jacey Yang 1F]

It depends on the units for pressure and volume given in the problem.

[Bryan Chen 1H]

on the equations sheet look at the units for R and make sure they match up with those given in the problem, or those that you may convert to/use

[RRahimtoola1I]

Here are the different gas constants. It depends on the units you are using in the equation. For PV=nRT you would usually use the 0.082.

[Edmund Zhi 2B]

The R constant will vary based on the other units given to us within a problem. Our formula sheet should always have a value of R that we will need to use in any problem on an exam.

[Rory Simpson 2F]

Just make sure that you choose the right R constant depending on the units for pressure and volume, or convert all the units so that you can 0.082 L*atm*mol^-1*K^-1.

[Jasmine Vallarta 2L]

it depends on the units of pressure given to you in the problem

[Michelle N - 2C]

How do you know which variation of the R constant to use?

I know that Test 1 is already over, but in the equations sheet that Dr. Lavelle provided, there were many variations of it. To answer your question, the best way to know which R constant to use is to see the units used in the problem. If it mentions atm, then it'll be the number with atm in the units. Same applies for J, and so forth.

[Shail Avasthi 2C]

The value of R you use depends on the units given to you in the problem and the units which your answer needs to be in. The units of R will cancel out with all of the given terms to give you your final answer's units.

[Maria Poblete 2C]

In the equation sheet we're provided with, there are a number of different values to use for the R constant. It's important to look at which units are being used, which will tell you which one is appropriate to use.

[SarahCoufal_1k]

It depends on the units of the other. variables provided. Choose the r with the matching units and all but the variable you are looking for should cancel out.

[Areli C 1L]

Depending on the units given, use the R constant that uses the same units in order for them to cancel and give the desired answer.

[RichBollini4G]

How do you know which variation of the R constant to use?

I would say look at the specific units of the problem.

[RichBollini4G]

The value of R you use depends on the units given to you in the problem and the units which your answer needs to be in. The units of R will cancel out with all of the given terms to give you your final answer's units.

Thank you

[Mandeep Garcha 2H]

It depends on the units given in the problem.

[Anushka Chauhan2B]

The one with similar units in the problem so that the units can cancel

[Indy Bui 1l]

The R constant is dependent on the units of pressure you are given. Looking up a table is helpful and just pay attention to the units you are given in the question. You don't need to memorize this, just know which values correspond to each unit of pressure.

[kendal mccarthy]

To determine which R to use view the givens you have and then you can determine which R unit would cancel out the appropriate units to get what value you desire. For most calculations, like in the VP=nRT equation, it will be 0.08206.

[vanessas0123]

Look at the units you have and match it with the R constant's units!

[Micah3J]

Just make sure that the R constant and your given units will cancel out and match accordingly

[Orrin Zhong 4G]

There are a lot of gas constants, so just fit the units that are involved with the units of the correct gas constant. Generally, I use 0.0821 Latm/(molK) when I'm trying to find volume or pressure and 8.314 J/(molK) when I'm trying to find energy.

[Joanne Lee 1J]

You can decide which form of R to use based on what the units of the given values are.

[Charlene Datu 2E]

When looking at the units, it's good to note which ones will cancel out, and to keep in mind the units that your answer is supposed to be in. For the ideal gas law, you will typically be using any value with a unit of pressure (atm, bar, Torr). When calculating anything related to energy, the values with units of J or L/atm (1 L atm = 101.325 J) are helpful.

[Jasmine W 1K]

It depends on the units given in the problem. All of the R constants mean the same thing; the numbers just change due to unit conversions.

[Jose Robles 1D]

Read the problem and see the units being used in the question, look at the pressure usually.

[Gurmukhi Bevli 4G]

It will normally depend on the units given for the other quantities being used in the problem, and the variations of R and its value/units will usually be given on the formula sheet, so it is easier to assess the units on a case by case basis and see which one is the best fit.

[Tahlia Mullins]

I always just look at the units given, and it’s usually pretty easy to tell. Sometimes, temperature might need to be changed to Kelvin though!