When to use PV nRT or PV NkT?

Use 𝑃 𝑉 = 𝑛 𝑅 𝑇 𝑃 𝑉 = 𝑛 𝑅 𝑇 in chemistry and general applications when you have the number of moles ( 𝑛 𝑛 ), using the molar gas constant 𝑅 𝑅 (e.g., 8.314 J/(mol·K)). Use 𝑃 𝑉 = 𝑁 𝑘 𝑇 𝑃 𝑉 = 𝑁 𝑘 𝑇 in physics and statistical mechanics when you have the number of individual particles ( 𝑁 𝑁 ), using the Boltzmann constant 𝑘 𝑘 ( 1.38 × 10 -23 1 . 3 8 × 1 0 − 2 3 J/K). Both describe ideal gases, just with different units for the count of gas units.

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

Say you're using the ideal gas law, the units will have to cancel to give you a correct answer. Because that equation uses pressure, volume, temp and moles, then you know you would use 0.08 L atm/mol K. However, if you're using an equation that deals with energy (like RTlnK), then use the 8.314 J/molK so units cancel.

When to use Boltzmann constant vs gas constant?

Boltzmann's constant is far, far better for doing any theoretical work and derivations. You're never going to write a Boltzmann factor as anything besides exp(-E/kT). However, the ideal gas constant is far, far easier to use for measurements and comparison to experiment.

When to use PV mRT vs PV RT?

However, there is a difference in Rs in Pv=mRT (Generally used in Engineering) and Pv=nRT (Generally used in chemistry). R used in engineering is per mass (kg) basis while R used in chemistry is in per matter (mol) basis.

When can PV NRT be used?

The equation of state given here (PV = nRT) applies only to an ideal gas, or as an approximation to a real gas that behaves sufficiently like an ideal gas. There are in fact many different forms of the equation of state.

PV=nRT, the Ideal Gas Law, what is it and how to use it

When to use PV nRT and when to use PV NkT?

Determine whether the number of molecules or the number of moles is known, in order to decide which form of the ideal gas law to use. The first form is PV = NkT and involves N, the number of atoms or molecules. The second form is PV = nRT and involves n, the number of moles.

Is STP 22.4 L or 22.7 L?

Both 22.4 L/mol and 22.7 L/mol are used for STP, depending on the definition of pressure, with 22.4 L/mol (at 1 atm) being the older, common standard, especially in older U.S. texts, while 22.7 L/mol (at 1 bar) is the newer IUPAC definition, so check your context or problem for the specific pressure (1 atm vs. 1 bar). 

What are the 5 assumptions of an ideal gas?

The five main assumptions of an ideal gas, based on the Kinetic Molecular Theory, are: particles are in constant, random motion, collisions are elastic (no energy loss), there are no intermolecular forces, the volume of particles is negligible compared to container volume, and temperature is proportional to average kinetic energy. These assumptions simplify gas behavior, though real gases deviate, especially at high pressures/low temperatures.
 

Which gas constant do I use?

To keep the ideal gas law correct and compatible, the units of the gas constant must match the other values you use in the equation. The value most people use is 8.314 J K-1 mol-1.

What is 1.38 x10^23?

This is the Boltzmann constant (k) which has a value of 1.38x10-23 JK-1. The Boltzmann constant = R/NA where R is the universal gas constant (R = 8.31 JK-1mol-1).

What is the relationship between k and R?

k value and R value are both measures of a material's resistance to heat flow. k value relates only to the type of material where R value also takes into account the material's thickness. A piece of material that is twice as thick as another piece of the same material has twice the R value.

Is 0.0821 always R?

No, the ideal gas constant R is not always 0.0821; its value changes depending on the units used for pressure, volume, and temperature, though 0.0821 L·atm/(mol·K) is common when using atmospheres (atm), liters (L), and Kelvin (K). Other common values include 8.314 J/(mol·K) for SI units (Pascals, cubic meters) or 62.4 L·mmHg/(mol·K), showing R is a constant, but its numerical value adapts to match the units in the Ideal Gas Law (PV=nRTcap P cap V equals n cap R cap T𝑃𝑉=𝑛𝑅𝑇).
 

What does R stand for in NRT?

In the ideal gas law equation PV=nRT, R stands for the universal gas constant, a fundamental constant that links the energy, pressure, volume, and temperature of a gas, with its specific value depending on the units used for the other variables (like pressure, volume, and temperature). Common values include 0.0821 L·atm/(mol·K) (for liters, atmospheres, moles, and Kelvin) and 8.314 J/(mol·K) (for SI units like Joules, Kelvin, moles, and cubic meters).
 

Is STP 22.4 or 24?

The values 22.4 L and 24 L (or 24.4 L) relate to the volume of one mole of gas, but at different conditions: 22.4 L is for Standard Temperature and Pressure (STP) (0°C, 1 atm), while 24 L (or ~24.4 L) is often used for Room Temperature and Pressure (RTP), typically 25°C and 1 atm, reflecting gas expansion with increased temperature. 

Is STP 1 atm or 1 bar?

STP (Standard Temperature and Pressure) has different definitions: the modern IUPAC standard uses 1 bar (100 kPa) at 0°C, while older definitions, often used in the US and for ideal gas law problems, use 1 atm (101.325 kPa) at 0°C. So, it can be either, but 1 bar is the current international chemical standard, whereas 1 atm is still common in many textbooks and applications. 

When can you use 22.4 L?

At Standard Temperature and Pressure (STP), 1 mole of any gas will occupy a volume of 22.4 L. The Ideal Gas Law, along with a balanced chemical equation, can be used to solve for the amount, either in volume or mass, of gas consumed or produced in a chemical reaction.

Is 1 mole equal to 22.7 L?

Standard Conditions of Temperature and Pressure

At STP , one mole of an ideal gas has a volume of about 22.7 L, which is referred to as the standard molar volume. Chemists often work at 1 atm pressure which was used in an older definition of STP, where one mole of any ideal gas gas has a volume of about 22.4 L.

When to use p V2 r and p i2r?

The experssion P = I 2 R is used ton calculate electric power when the current flowing through the circuit is constant. This is the case when the electric devices are connected in series. The expression P = V 2 / R is used to calculate electric power when the pd (v) across the circuit is constant.

Is R 8.314 or 8314?

The value of the universal gas constant Rcap R𝑅 is 8.314 J/(mol·K) (Joules per mole-Kelvin) when using SI units (Pascals, cubic meters) in the ideal gas law (PV=nRTcap P cap V equals n cap R cap T𝑃𝑉=𝑛𝑅𝑇), but it's 8314 J/(kmol·K) when using kilomoles (kmol) for the amount of substance, making 8.314 the common value and 8314 the same value just scaled for different units. You choose the value based on the units of your other variables (Pressure, Volume, Moles, Temperature). 

Is the molar volume of 22.4 or 24?

Complete answer: At STP, one mole ( 6.02 × 10 23 representative particles) of any gas occupies a volume of 22.4 L . A mole of any gas occupies 22.4L at standard temperature and pressure (273K and 1atm).

What is 0.287 gas constant?

Properties The gas constant of air is 0.287 kPa. m3/kg. K (Table A-1). The specific heat of air at the anticipated average temperature of 450 K is Cp = 1.02 kJ/kg.

What is the ideal gas cycle?

The ideal gas cycle operates under the assumption that the working substance behaves according to the ideal gas law, which states that pressure times volume equals temperature times a constant (PV=nRT). In the ideal gas cycle, work can be calculated by the area under the process curves on a pressure-volume diagram.