CHI 201 ch 0 Flashcards
(25 cards)
What is the general form of a chemical reaction at equilibrium?
A + B -> <- C + D
What is a characteristic of a reaction at equilibrium?
The reaction occurs in both directions at the same rate.
What indicates a total reaction?
At least one reactant is in negligible quantity at the end of the reaction.
What must be conserved when balancing a chemical reaction?
Conservation of matter and conservation of total charge.
Provide an example of a balanced redox reaction.
2H2 + O2 -> 2 H2O
Can negative stoichiometric coefficients be used in balancing reactions?
No, negative stoichiometric coefficients are not allowed.
What does electroneutrality refer to in a dissolution example?
[H+] + [K+] = [HO-] + 2[SO42-]
What is the definition of the activity of a compound i?
Ai = a dimensionless quantity characterizing the behavior of species i.
How is activity defined for a solute?
ai = ϒi * [Ai]/ C0
What is the activity of a dilute solution?
ϒi = 1
How is activity calculated for a gas?
ai = Pi/P0
What is the activity of a solid or solvent?
ai = 1
What is the equilibrium constant expression?
K = [aC] * [aD] / [aA]* [aB]
What does the equilibrium constant K depend on?
The reaction and temperature.
What is the relationship between K and pK?
pK = -log10 K
What happens to pK when K increases?
pK decreases.
State Le Chatelier’s principle.
If a system is subjected to a disturbance, it will react to counteract that disturbance.
What happens to the reaction when a reactant is added?
The reaction shifts to the right (towards products).
What effect does increasing temperature have on an endothermic reaction?
The reaction shifts to the right.
What effect does increasing pressure have on a reaction?
The reaction shifts towards the side with fewer moles of gas.
What does a reaction progress table describe?
The evolution of quantities of substances from initial to final state.
What information is found in the first line of the reaction progress table?
The balanced equation of the reaction.
What information is found in the subsequent lines of the reaction progress table?
Initial quantity, quantity at time t, and quantity at equilibrium.
What is a limiting reactant?
The reactant that is completely consumed first.
