CHEM Test 3

Question 1

0th Law of Thermodynamics

Answer 1

Transitive law of thermodynamics. Systems in thermal equilibrium with a third system are in thermal equilibrium with each other.

Question 2

1st Law of Thermodynamics

Answer 2

Law of Conservation of Energy, ΔE=q+w “you can’t get out more than you put in.”

Question 3

2nd Law of Thermodynamics

Answer 3

directionality of energy flow, higher to lower order energy, “the rock won’t come back”

Question 4

3rd Law of thermodynamics

Answer 4

a pure crystal at absolute zero has perfect order: zero entropy.

Question 5

Specific Heat Capacity

Answer 5

The quantity of heat need to change 1.00g of a substance by 1.00K

Question 6

Heat (q)

Answer 6

transfer of thermal energy from hotter to cooler region an extensive property

Question 7

temperature

Answer 7

an intensive property, the quantity that is always the same when two systems are in thermal equilibrium, the measure of the hotness of coldness of a system relative to an arbitrary standard

Question 8

bomb calorimeter

Answer 8

closed system, not under constant pressure

Question 9

ice calorimeter

Answer 9

open system, under constant pressure

Question 10

styrofoam cup calorimeter

Answer 10

open system, under constant pressure

Question 11

enthalpy

Answer 11

energy change during a reaction, ΔH=q_p

Question 12

state function

Answer 12

quality determined only by the state of system, NOT by path, (H) path INDEPENDENT

Question 13

“standard conditions” (º)

“standard state”

Answer 13

1 bar pressure and a stated temperature (usually 298K)

pure at standard conditions, and at a specified temperature, usually 298K

Question 14

reference state

Answer 14

most stable standard state at 1 bar and a specified temperature. Example: the reference state of water at 298K and 1 bar is pure liquid, the reference state of carbon at 1 bar and 298K is pure graphite, not diamond, the reference state of H₂ at 1 bar at 298K is pure gas

Question 15

standard molar enthalpy of formation

Answer 15

ΔH_f the standard enthalpy change for the formation of 1 mole of a substance from its elements in their *reference *states (pure, most stable form at 1 bar and stated temperature, usually 298K)

ΔH°rxn = Σ ΔH°f (products) minus Σ ΔH°f (reactants)

Question 16

standard enthalpy change (ΔHº)

Answer 16

enthalpy change for a reaction where reactants and products are in their standard states

Question 17

ppm

Answer 17

parts per million,

1 mg/L

Question 18

ppb

Answer 18

parts per billion

1 µg/L

Question 19

internal energy

Answer 19

The internal energy in a chemical system is the sum of the potential and kinetic energies inside the system, that is, the energies of the atoms, molecules, or ions in the system.