Quiz II: Expansion Processes & Entropy Changes

University:
The Pennsylvania State University
Course:
CHEM 450 | Thermodynamics
Academic year:

2024
Views:

167

Pages:

1
Author:

Alexis H.

Name__________________ Chem. 450 Quiz II (5 points) Feb. 24, 2023 (1) (2 points) Consider a gas which expands reversibly inside a cylinder from 1 L to 5 L. (a) Draw a curve on a pressure vs. volume diagram showing the expansion process if it occurs isothermally. (b) On the same diagram, starting from the same initial point, draw a curve for the expansion process if it occurs adiabatically. Please label your axes and the two curves on the diagram. (c) In which expansion process does the system do more work on the surroundings? the isotherm does more work on the surroundings p isotherm adiabat V (2) (2 points) On a cold winter day, the water in a lake freezes to form ice. You may consider the water in the lake to be the system. (a) What is the sign (plus, minus, or zero) associated with Ssys, Ssurr, and Stot for this process. (b) Which one is greater, the absolute value of Ssys or the absolute value of Ssurr associated with this process? a ΔSsys b they would be equal so ΔSsurr Δ5 o thatΔS would equal zero 0 (3) (1 points) Two moles of a liquid are heated from 25 °C to 50 °C under constant pressure conditions. The molar heat capacity for this liquid, Cp,m, is constant over the entire temperature range. Calculate the entropy change associated with this heating process. Note: dS = dqrev/T and dH = dqrev and dHm = Cp,mdT as fer Cpmdt ds T as 2 If 1.5 monk