Chem 125 Study Guide

True or False: A spontaneous reaction has a - Delta G and a Q value less than its K value

True

True or False:A product favored reaction has both a large K and a +DG

False

When a system is at equilibrium, which of the following is true?

All of the concentrations of reactants and products have reached a constant value

For a reaction, the rate law is Rate = k[A][B][C].What are the units for k where the time unit is seconds and the concentration unit is M?

M^-2s^-1

A reactant R is being consumed in a first order reaction. what fraction of the initial R concentration remains after 3 half-lives?

12.5%

An increase in which of the following will NOT produce an increase in the rate of a chemical reaction?

Activation Energy

A catalyst increases the rate of or "speeds up" a reaction by

lowering the activation energy of the reaction

What is a reversible reaction, and under what condition does equilibrium occur in such a reaction?

A reaction that can occur in both the forward and the reverse direction is said to be reversible. When the rate of the forward reaction equals the rate of the reverse reaction, we say the reaction is at equilibrium

What is the difference between Kc and Kp for a chemical reaction?

Kc is the equlibrium constant when reactants and products are expressed in concentration units. Kp is the equilibrium constant when reactants and products are expressed in pressure units. You should be able to write expressions for both, and we can conver

What is the reaction quotient of a reaction, and what is the relationship between Qc and Kc

The reaction quotient has the same form as Kc, but the concentrations are not necessarily at equilibrium. The reaction quotient can be used to predict the direction that a reaction will move to attain equilibrium. At equilibrium Qc=Kc

Is the following statement true or false? " reactions with large equilibrium constants are very fast". Explain your answer

Kc only indicates the balance between reactants and products. In this way a large Kc indicates that products will be favored at equilibrium but says nothing about how fast equilibrium is achieved.