Exam 3 Review!

Mole Conversions

100

2Al + 6HCl ---> 2AlCl₃ + 3H₂

How many Moles HCl are needed to react with 2.4 Moles Al?

7.2

200

How many grams O₂ are needed to react with 25.0 moles of C₁₀H₈?

C₁₀H₈ + 12O_{2 --->} 10CO₂ + 4H₂O

9.60 x 10^3

300

How many grams NaCN can be produced from 174 grams Ca(CN)₂?

Ca(CN)₂ + 2NaCl ---> CaCl₂ + 2NaCN

185 g

400

What is the equation for percent yield? 

If the actual yield is 134g Al and the percent yield is 60.5%, what is the theoretical yield?

Actual/Theoretical x 100%

221g Al

500

When 50.0g copper was reacted with silver nitrate solution, 148 g of silver (Ag) was obtained. What is the percent yield of Ag obtained?

Cu + 2AgNO₃ ---> Cu(NO₃)₂ + 2Ag

87.1%

Oxidation Numbers

100

Oxidation # of Fe in FeCl₂

2+

200

What are the Oxidation #'s in a polyatomic ion equal to?

0!

300

Oxidation number of Ca₂Mn₂S₇

+5

400

Ox # of C in CS₂^3-

1+

500

What are the reducing and oxidizing agents in:

2KClO₄ ------> KCl + 2O₂

Oxygen = reducing agent

Cl = oxidizing agent

Rates of Reaction

100

Reaction rate increases by:

An increase in Temperature,

An increase in Reactant Concentration,

An increase in pressure,

Presence of a catalyst

200

What is the activation energy and how is it reduced?

The peak of reaction-reactants. Reduced by a catalyst.

300

What does a small Kc mean?

Reactants are favored and the equilibrium lies to the left!

400

The products go on the bottom in an Equilibrium Constant, using subscripts as their powers.

True or False?

False

500

Kc if KCLO₄ = 2.4M, KCL = 1.2M, and O₂ = .86

2KClO₄ ------> KCl + 2O₂

.16

Energy of Reactions

100

What is an exothermic reaction?

Heat on the reactants or products side?

Product! (- delta H)

200

What is entropy?

Disorder of a system!!

300

2H₂O(l) + CCl₄(aq) --> 3O₂(g)+ HCl(g) + 2CO(g)

5 HCl(g) + 6CO₂(g) ---> 5 H₂O(l) + 6 CCl(l)

2O₂(g) + H₂(g) --->  2OH(g)

Which has a Delta S > 0?

2H₂O(l) + CCl₄(aq) --> 3O₂(g)+ HCl(g) + 2CO(g)

(Points away from reactants, to products!)

400

Which results in a reaction never being spontaneous?

+ change in H, + change in S

- change in H, - change in S

+ change in H, - changed in S

- change in H, + change in S

+ change in H, - changed in S

Results in a + delta G every time!

500

How do you find the change in H or the change in G from a graph?

Free energy change equation: Change G = Change in H - T(Change in S)

True or False?

Products - Reactants! Always!

True!

Le Chatalier's Principle

100

Decreasing temperature will:

H₃O(g) + 3 CO(g) <=> CO₂(g) + OH(l) + Heat

Shift the equilibrium right/to products

200

Remove H₃O will cause:

H₃O(g) + 3 CO(g) <=> CO₂(g) + OH(l) + Heat

A shift left/to reactants

300

Increasing Pressure:

2OH(g) + CO₂(g) <=> H₃O(g) + 7O₂(g)

shift left/to reactants

400

Increasing concentration of CCl₂:

HCl₂(g)+CO₂(g) <=> CCl₂(aq) + 4 H₂O(l)

Does CCl₂ increase or decrease?

Shift to left/reactants 

CCl₂ increases, right side of reaction decreases.

500

HCl₂(g)+CO₂(g) <=> CCl₂(aq) + 4 H₂O(l)

(This equation has a - delta H)

Does entropy increase towards products?

Will decreaseing temperature will shift equillibrium to the left?

What will increasing the amount of H₂O do?

No

No

Shift left/to reactants