chapter 18 – reaction rates and equilibrium

Chapter 18 – Reaction Rates and Equilibrium

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Rates of Reactions

Equilibrium Entropy and Free Energy

Le Chatelier’s Principle

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Row 1, Col 1

The rate of a chemical reactionmay be increased by increasing the _______ and / or ________.

Temperature or concentration of reactants

1,2

When a reaction reaches equilibrium, what can you say about the rate of the forward reaction and reverse

reaction?

They are equal.

1,3

What is the name and the symbol of the term used to describe the

‘disorder’ of a process?

Entropy (S)

1,4

Decreasing the temperature of thefollowing reaction at equilibrium

will cause it to shift in whichdirection?

N2(g) + 3H2(g) + Energy 2NH3(g)

Left Shift

2,1

As the particle size of a reactantdecreases, the rate of reaction

will __________.

Increase

2,2

What can you conclude about a chemical reaction that has reached equilibrium were the equilibrium

constant (Keq) is less than one?

Reactants are favored at equilibrium.

2,3

Is there an increase or decrease inThe entropy in the following process?

CaCO3(s) CaO(s) + CO2(g)

Increase

2,4

What will happen to the position of the equilibrium when the the pressure is raised

on the following chemical reaction?PCl5(g) PCl3(g) + Cl2(g)

It will shift to the left.

3,1

How does a catalyst speed up a chemical reaction?

It lowers the activation energy.

3,2

Write the equilibrium expression for the following chemical reaction; 4H2(g) + CS2(g) CH4(g) + 2H2S(g)

Keq = [CH4] [H2S]2

[H2]4 [CS2]

3,3

Which two factors together determineif a reaction is spontaneous or not?

Entropy (S) and Enthalpy (H)

3,4

What effect will the addition of KClO4 have on the following

Equilibrium?KClO4(s) KCl(s) + 2O2(g)

No effect, Keq = [O2]2

4,1

What is the unit usually used to expressthe rate of a chemical reaction?

Molarity / time

4,2

Write the solubility product expression,Ksp, for the dissolution of

lead (IV) carbonate.

Ksp = [Pb+4] [CO3-2]2

4,3

If the entropy and enthalpy of a chemical reaction both decrease,

what can you conclude about the spontaneity of the reaction?

It may or may not be spontaneous.

4,4

Reducing the temperature on the followingreaction will cause it to shift in which

direction?N2(g) + 3H2(g) + Energy 2NH3(g)

left

5,1

Write the rate law for the followingchemical reaction;

N2(g) + 3H2(g) 2NH3(g)

Rate = k [N2] [H2]3

5,2

What will the addition of NaCl doTo a saturated solution of PbCl2?

The addition of Cl- would cause PbCl2 to precipitate.

5,3

The following chemical reaction (will / will not) be spontaneous.

C3H8(g) + 5O2(g) 3CO2(g) + 4H2O(g) + Energy

will

5,4

What effect would adding water tothe following reaction have on its

equilibrium position?Na(s) + 2H2O(l) 2NaOH(aq) + H2(g)

No effect

Final Jeopardy • What is the concentration of carbonate

ions in a saturated solution of SrCO3?

Ksp = 9.3 x 10-10