Equilibrium

2NH3(g)  N2(g) + 3H2(g) At 500 K, the following concentrations were measured: [N2] = 3.0 x 10-2 M, [H2] = 3.7 x 10-2 M, [NH3] = 1.6 x 10-2 M. What is Kc?

• 5.3  10-3

• 5.9  10-3

• 4.7  10-3

At 1000 K, the equilibrium partial pressures for the reaction below are: CH4 = 0.20 atm, H2S = 0.25 atm, CS2 = 0.52 atm, and H2 = 0.10 atm. What is Kp?

• 4.2  10-3

• 4.9  10-3

• 3.8  10-3

For the reaction, B  2A, Kc = 2. Suppose 3.0 moles of A and 3.0 moles of B are introduced into a 2.00 L flask.

• .4

• 4.2

• 1.5

If a system at equilibrium is subjected to a ____________ , the equilibrium is displaced in the direction that relieves the ____________.

• stress,stress

• rate,stress

• rate,rate

When, because of an applied stress, the forward reaction is faster than the reverse reaction, the system is said to shift to the (right, left). As a result, the [products] will (increase, decrease) and the [reactants] will (increase, decrease).

• right,increases,increases

• right,increases,decreases

• left,increases,decreases

When, because of an applied stress, the reverse reaction is faster than the forward reaction, the system is said to shift to the (right, left). As a result, the [products] will (increase, decrease) and the [reactants] will (increase, decrease).

• left,decrease,increase

• left,increase,decrease

• right,decrease,decrease

A reaction reaches equilibrium when the reactants are all used up. ( True/False )

• true

• false

A chemical reaction that can occur in only one direction is called a(n) _____ reaction.

• reversible

• equilibrium

• irreversible

A chemical reaction that can occur in both directions is called a(n) _____ reaction.

• irreversible

• reversible

• equilibrium

Which of these chemical changes is reversible?

• wood burning in a campfire

• a cake baking in the oven

• calcium carbonate decomposing

• two of the above