The SI unit of R in General Gas equation is:
Correct answer: A. 8.3143 JK⁻¹mol⁻¹
- A. 8.3143 JK⁻¹mol⁻¹
- B. 0.0821 dm³atom mol⁻¹K⁻¹
- C. 8.3143 Jmol⁻¹
- D. 0.0821 dm³tor K⁻¹mol⁻¹
Explanation
The SI unit of R (the ideal gas constant) in the General Gas equation (PV = nRT) is 8.3143 J K⁻¹ mol⁻¹ (Joules per Kelvin per mole). Here's how we derive this: Ideal Gas Equation: PV = nRT P = pressure (Pascals, Pa or N/m²) V = volume (cubic meters, m³) n = number of moles (mol) R = ideal gas constant T = temperature (Kelvin, K) Rearranging the equation to solve for R:R = PV / nT Now, let's look at the units: Pressure (P): Pa = N/m² = kg⋅m⁻¹⋅s⁻² Volume (V): m³ Number of moles (n): mol Temperature (T): K So the units of R are:(kg⋅m⁻¹⋅s⁻²)⋅m³ / (mol⋅K) = kg⋅m²⋅s⁻²⋅K⁻¹⋅mol⁻¹Since 1 Joule (J) is equal to 1 kg⋅m²⋅s⁻², the SI units of R can also be written as:J⋅K⁻¹⋅mol⁻¹ or J/(K⋅mol)The value of R is approximately 8.314 J K⁻¹ mol⁻¹.
Last updated
About Ideal Gas Equation
The ideal gas equation, PV = nRT, relates pressure, volume, amount and absolute temperature when gas particles are assumed to have negligible volume and no intermolecular forces. Applications include finding molar mass, density or an unknown gas variable, with careful use of Kelvin temperature and consistent units, and comparison with real-gas behaviour.
Practise Gases
443 free Gases MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Chemistry questions like this
Chemistry is on 12 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
0.2 g of a gas X occupies a volume of 0.44 L at same pressure and temperature. Under identical conditions of P and T, 0.1 g of CO2 gas occupies 0.32 L. Gas X can be :
0.20 g of carbon dioxide at 25 °C has 844 torr pressure. After heating, the pressure increases to 2.24 atm. What is the temperature?
1 liter flask contains nitrogen along with a drop or two of water at 40° C, the total pressure being 760 Torr. If all the contents are transferred to another flask of 0.5L at the same temperature. The pressure of nitrogen setup in the second flask will be: (aqueous tension at 40 °C 55 torr):
1 liter of a gas weighs 2 g at 300 K and 1 atm pressure. If the pressure is made 0.75 atm, at which of the following temperatures will 1 L of the same gas weigh 1 g?
100 m3 of a gas at 3 atm pressure and 27 oc is transferred to a chamber of 300 m3 volume maintained at a temperature of 327 oc. What will be the pressure in chamber?