Question

1L-atm is equal to
A. 10.13 J
B. 101.3 J
C. 1013 J
D. 1.013 J

Answer 1

Hint: Atmospheric pressure is generally the pressure exerted by the atmosphere. It is also known as barometric pressure as the pressure is measured by the instrument known as barometer. In most cases the atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point.

Complete answer:
Pressure generally measured by force per unit area. Litre atmosphere is a unit of work which can be defined as the work made by a pressure of 1atmosphere that expands a gas volume of 1 litre. Litre-atmosphere unit is used to measure energy. It was originally defined as the pressure exerted by 760 mm of mercury at ${{O}^{{}^\circ }}$C and standard gravity is given by 9.80665$m{{s}^{-2}}$. It can be used as a reference condition for physical and chemical properties and was identified in the definition of the centigrade scale of temperature by defining ${{100}^{{}^\circ }}C$as being the boiling point of water at this pressure.
1L-atm is always equal to 101.3 J, Joule is the secondary unit of pressure while primary is L-atm.

Hence we can say that option B is the correct answer.

Note: In chemistry and in many industries the reference pressure always referred to in STP conditions means standard temperature and pressure which is commonly 1 atm and 101.325 kPa, where kpa is equal with joules meaning kilopascal.