U5 Solubility and Equilibrium

1. When is chemical equilibrium achieved?

a.	when both the forward and reverse reactions stop
b.	when all of the reactants are used up
c.	when the concentration of products and reactants become equal
d.	when the rates of the forward and reverse reactions are equal
e.	all of the above

2. In the equilibrium constant expression below, what do the exponents represent?

 

a.	the concentrations of reactants and products
b.	the equilibrium constant
c.	the rates of the forward and reverse reactions
d.	the stoichiometric coefficients from the balanced equation
e.	none of these

3. A system has reached chemical equilibrium. Which is true of the system?

a.	there is no net change in the concentration of reactants or products
b.	the molecules have stopped combining and decomposing
c.	the system is open
d.	there is no change taking place
e.	All of the above are true

4. Which of the following systems would be considered to be at equilibrium:

I. an open flask with 2.0 mL of perfume

II. a closed flask with 10 mL of water

III. an open flask with 10 mL of water

IV. closed flask with ice cube and 10 mL of water

a.	I	c.	II & IV	e.	III
b.	I & II	d.	II

5. When a catalyst is added to a chemical system involving a reversible reaction, the catalyst __________.

a.	increases the rate of reaction in both directions
b.	increases the rate of reaction in the forward direction only
c.	increases the rate of reaction in the reverse direction only
d.	has no effect on the rate of reaction in either direction
e.	shifts equilibrium in one direction

6. A very large value of   indicates that _____________.

a.	the reaction reaches equilibrium quickly
b.	the reaction doesn’t reach equilibrium quickly
c.	the reaction makes a lot of product
d.	the reaction does not make a lot of product
e.	the reaction is irreversible

7. What does it mean if   < 1, at equilibrium?

a.	The concentration of reactants is greater than the concentration of products.
b.	The concentration of products is greater than the concentration of reactants.
c.	The rate of the forward reaction is greater than the rate of the reverse reaction.
d.	The rate of the reverse reaction is greater than the rate of the forward reaction.
e.	The concentration of products and reactants are about the same.

be able to establish/differentiate between rate and concentration graphs

explain iodine experiment and its counter exp.