Gases and Thermochemistry
standard pressure and temperature of a gas
0℃ and 1 atm
ratio of forward and reverse rates of reaction at equilibrium
One. (they are equal)
What are 3 actions that can increase the rate of dissolution of a solid in water?
A proton acceptor
Brønsted-Lowry base
For the reaction : A + 2B + 3 C --> D
What is the limiting reactant if you mix 4 mol A, 4 mol B and 9 mol C together?
B
what affects the rate of diffusion or effusion?
the size (molar mass) of the gas - the smaller the gas the faster the diffusion
In terms of solubility, s, what is the expression for Ksp for Be(OH)2 ?
Ksp = 4s3
a measure of disorder in a system
entropy
An HF solution with a pH = 1 is weak or strong? dilute or concentrated?
Weak and Concentrated
The two assumptions made to use the simplified expression for the hydronium concentration of a weak acid solution: [H+] = √(Ka[HA]init)
(1) [H+] from water is negligible: pH < 6
(2) Percent ionization,100% x [H+]/[HA]init , is < 5%
How the volume of a gas changes if the Kelvin temperature doubles and the pressure quadruples
What is become halved
For the reaction N2 +3H2 --> 2NH3
If you mixed 0.2 M N2 and 0.3 M H2 , what would the concentrations of all 3 species be at equilibrium be in terms of x, the change in concentration of N2 ?
N2 0.2 - x
H2 0.3 - 3x
NH3 2x
"like dissolves like" refers to
similar polarity
In the reaction represented by the equation:
HCO3-1 + H2O → CO3-2 + H3O+
What is CO3-2 ?
Conjugate Base
Given the voltaic cell represented as Fe|Fe2+||Au3+|Au
Which way do electrons flow, which metal is gaining in mass, and which metal is being reduced?
Electrons flow from Fe cell to Au cell; Au is gaining mass AND Au3+ is being reduced
RAPIDFIRE: Name a phase change; state what it is (e.g. liquid to solid) and if it is exothermic or endothermic
ENDOTHERMIC: melting (s->L); boiling (L -> G) sublimation (S -> G)
EXOTHERMIC: freezing (L -> S); condensation (G ->L); deposition (G -> S)
You have the reaction A + B --> C with Keq and Ecell
How does Keq and Ecell change if the reaction is 2A + 2B --> 2C?
Keq is squared. Ecell does not change
present in greatest amount in a solution
what is a solvent
This type of acid/base titration has an equivalence point at pH < 7
Strong acid/weak base
Term for the reactant that remains after a reaction runs out of one of the reactants
what is excess
A measure of the kinetic energy of a system
temperature
Given the reaction N2 +3H2 --> 2NH3 ∆H= -46 kJ
What will happen to the concentration of H2 if the temperature increases? If more N2 is add to the reaction vessel?
Temp: INCREASE
N2: DECREASE
When is the reaction:
SnCl4 (l) + 2 H2O (l) --> SnO2 (s) + 4 HCl (g) ∆H + +133kJ
thermodynamically favored?
at HIGH temperature
a substance that can act as an acid or a base
amphoteric
What do the following acronyms mean? OILRIG, AN OX, FATCAT
OILRIG: Oxidation Is Loss of electrons; Reduction Is Gain
AN OX: oxidation occurs at the anode
FATCAT: electrons flow From the Anode TO the CAThode