# How do I decide whether to use 0.0821 or 8.314 for R?

The only time R = 0.082 is used is when the pressure is expressed in atm and volume in liters. R = 8.314 is a much more common and important value when pressure and volume are expressed in SI units, whether Pa and m^3 or kPa and L.

## How do you know which R value to use in chemistry?

The Gas Constant (R) It is crucial to match your units of Pressure, Volume, number of mole, and Temperature with the units of R. If you use the first value of R, which is 0.082057 L atm mol-1K-1, your unit for pressure must be atm, for volume must be liter, for temperature must be Kelvin.

## What are the different R values in chemistry?

• R = 0.0821 liter·atm/mol·K.
• R = 8.3145 J/mol·K.
• R = 8.2057 m3·atm/mol·K.
• R = 62.3637 L·Torr/mol·K or L·mmHg/mol·K.

## Which R constant is used with atm?

The value of R at atm that is at standard atmospheric pressure is R = 8.3144598 J.

## What is R in chemistry ideal gas law?

The factor “R” in the ideal gas law equation is known as the “gas constant”. R = PV. nT. The pressure times the volume of a gas divided by the number of moles and temperature of the gas is always equal to a constant number.

## What does R mean in the ideal gas law?

The ideal gas law is: pV = nRT, where n is the number of moles, and R is universal gas constant.

## How do you memorize R values?

1. R refers to Alkyl group.
2. R also refers to rectus ( Right Hand direction) in R& S nomenclature.
3. In physical chemistry R is used as a Universal Gas constant.

## When can you use ideal gas law?

The ideal gas law can be used in stoichiometry problems in which chemical reactions involve gases. Standard temperature and pressure (STP) are a useful set of benchmark conditions to compare other properties of gases. At STP, gases have a volume of 22.4 L per mole.

## Why the gas constant R is called universal gas constant?

Solution : The value of gas constant R is same for all `gases_t` and is independent of the nature of gas. Hence it is called universal gas constant.

## What is the value of R in ATM L mol K?

P = Pressure (atm) V = Volume (L) n = moles R = gas constant = 0.0821 atm•L/mol•K T = Temperature (Kelvin) The correct units are essential.

## What is R in chemistry structure?

Often when drawing organic structures, chemists find it convenient to use the letter ‘R’ to designate part of a molecule outside of the region of interest. ” R” represents the “Rest of the Molecule”.

## Which is the value of R?

The value of R depends on the units involved, but is usually stated with S.I. units as: R = 8.314 J/mol·K (also R = 8.314 Joules/Kelvin.) It is crucial to match your units of Pressure, Volume, number of mole, and Temperature with the units of R.

## How do I use different values in R?

If you are using all other values in SI units (e.g. Pressure in Pa, Volume in m^3 and Temperature in K) then you should use R=8.314 J/mol/K. But if you are taking Pressure in atm unit, volume in L and Temperature in K then you should use R=0.0821 L-atm/mol/K.

## What is the difference between ideal gas law and combined gas law?

The combined gas law is effectively a restructuring of the ideal gas law, where both n (mols of gas) and R (already a constant) remain constant. It can be used to determine how changes in pressure, volume, or temperature can be used to calculate the conditions of the resulting system.

## What law is P1V1 T1 P2V2 T2?

Combined gas law: P1V1/T1 = P2V2/T2 Use the gas laws for pressure, volume and temperature calculations. Avagadro’s law – Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.

## Does R depend on nature of gas?

Solution : R is the universal gas constant. Its value is independent of the pressure, volume, temperature or nature of the gas. The value depends only the units of measurement.

## On what factors does the value of universal gas constant R depend?

The value of the universal gas constant R depends on the units used for pressure, volume and temperature. Therefore, it depends on the units of measurement.

## Does the universal gas constant apply to all gases?

The universal gas constant R has a value of 8.314 J/mol · K in SI units. The constant R is the same for all ideal gases and hence it is called the universal gas constant.

## What does R1 mean in chemistry?

These three corresponding functional groups are R1 = aldehyde, R2 = ether. and R3 = hydroxyl.

## What are the different R groups?

There are basically three major classifications for amino acids (1) those with nonpolar R group, (2) those with uncharged polar R groups, and (3) those with charged polar R group.

## What do R groups do?

The R groups have a variety of shapes, sizes, charges, and reactivities. This allows amino acids to be grouped according to the chemical properties of their side chains. For example, some amino acids have polar side chains that are soluble in water; examples include serine, threonine, and asparagine.

## What is the value of π?

Succinctly, pi—which is written as the Greek letter for p, or π—is the ratio of the circumference of any circle to the diameter of that circle. Regardless of the circle’s size, this ratio will always equal pi. In decimal form, the value of pi is approximately 3.14.