Midterm 2 Flashcards
(40 cards)
First law of thermodynamics
a system’s energy changes if it exchanges energy with the environment via heat or work
Pressure-volume work
if the system’s volume doesn’t change then no work is performed
Heat capacity
the amount of heat needed per temperature change
Entropy
a measure of disorder
Delta S is greater than zero
spontaneous if it increases the entropy of the universe
Delta S is less than zero
spontaneous in the reverse direction if it decreases the entropy of the universe
Delta S is equal to zero
equilibrium
Delta G is less than zero
spontaneous if it decreases the system’s GFE
Delta G is greater than zero
spontaneous in the reverse direction if it increases the system’s GFE
Delta G is equal to zero
equilibrium
Vapor pressure
the pressure when a liquid is in equilibrium with its vapor
Clausius-clapeyron equation
allows us to estimate the vapor pressure at another temperature
Boiling occurs if…
the vapor pressure of a liquid equals the pressure of the environment
At the transitions on a heating curve chart (2,4)
the temperature doesn’t change even though heat is added, the enthalpy changes
A solution is…
a homogeneous mixture of a solute and a solvent
Solute
thing being dissolved
Solvent
dissolving agent
Solubility of solids typically…
increases with increasing temperatures
According to Henry’s Law…
the concentration of a gas dissolved in solution is proportional to its partial pressure
Solubility of gases typically…
decreases with increasing temperatures
Colligative properties
properties of solutions that depend on concentration of solutes, not on their chemical identity
Examples of colligative properties are…
lowering vapor pressure, elevation of BP, depression of FP, and osmosis
BP elevation
adding a non-volatile solute to the liquid increases entropy and decreases GFE and it raises the boiling point
Increasing the temperature of a liquid will cause it boil when the…
GFE of the gas equals that of the liquid
