In a lab setting, knowledge of the ideal gas law can be useful to understand wha
ID: 476761 • Letter: I
Question
In a lab setting, knowledge of the ideal gas law can be useful to understand what is remaining constant in a system and what is changing. In each of the following examples, make a comparison (either written or in a table) of what properties are being held constant and what are variable in PV=nRT. Justify your answers. A reaction is producing hydrogen in an open beaker on the bench top (no hotplate) [DON'T TRY THIS AT HOME] A reaction is producing CO_2 gas in a closed fume hood CO_2 gas is produced in a bomb calorimeter Liquid nitrogen is evaporating off of the bench top A balloon is being filled with He Water vapor is condensing on the side of a glass A piston is compressing an ideal gasExplanation / Answer
a)
In an open beaker, pressure of the reaction mixture will be equal to atmospheric pressure. P = constant
V, n and T will be variables as they will depend on extent of reaction.
b)
In a closed system, volume containing the gas produced will be equal to hood volume. V = constant
P, n and T will be variables as they will depend on extent of reaction.
c)
For a known amount of produced gas in a bomb calorimeter, no of moles and volume of the system will be constant. n, V = constant.
P and T will be variables, and have to be calculated based on heat absorbed by bomb calorimeter system.
d)
In an open system, pressure of the vapors will be equal to atmospheric pressure, P = constant. Vapor temperature can be taken to be same as atmospheric temperature, T = constant.
V and n will be variables as they will depend on extent of evaporation.
e)
Balloon pressure will always be in equilibrium with atmosphere, P = constant. Balloon temperature will be equal to He gas temperature, T = constant.
V and n will be variables as they will depend on the final size of the balloon.
f)
In an open system, pressure of the vapors will be equal to atmospheric pressure, P = constant. Water vapor temperature can be taken to be same as atmospheric temperature, T = constant.
V and n will be variables as they will depend on extent of condensation.
g)
No. of moles of gas in the system will be constant, n = constant. There will be negligible change in temperature due to compression. Therefore, temperature can be assumed to be constant, T = constant.
P and V will be variables as they will depend on extent of gas compression or final volume of gas.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.