Final Jeopardy

1
Final Jeopardy

• Subterm 2
• Solutions
• Equilibrium
• Acids Bases
• Thermochemistry
• Redox
• Nuclear Chemistry
• Organic Chemistry

2
THERMO

• Calculate the ?H for this reactionC2H4(g)
  H2(g) ? C2H6(g)
• (?H ?f for C2H4(g) 52.5 kJ/mol
• ?H?f for C2H6(g) -84.7 kJ/mol)

3
Solutions

• What is the maximum amount of KCl that can
  dissolve in 500 g of water?
  
  
• (solubility of KCl is 34 g / 100 g H2O at 20?C)

34 x 5 170 g
4
Solutions

• What three operations makes a substance dissolve
  faster in a solvent?

Heating Agitation/stirring Smaller surface
area/particle size
5
Solutions

• If the solubility of a particular solute is
  10g/100g H2O at 20?C, what solution
  concentrations would represent a supersaturated
  aqueous solution of that solute?

1. 5g/100g H20
2. 20g/200g H20
3. 25g/300g H20
4. 55g/500g H20

6
Solutions

• What is the molarity of a solution that contains
  6 moles of solute in 2 liters of solution?

6mol/2L 3M
7
Solutions

• What mass of sucrose, C12H22O11, is needed to
  make 500.0 mL of a 0.200M solution?

0.200M x/0.500L X 0.1mol x (342g/mol)
34.2 g
8
Solutions

• To 205 mL of a 0.75M solution of KI, a student
  adds enough water to make 1.5 L of a more dilute
  KI solution. What is the morality of the new
  solution?

M1V1 M2V2 M2 0.10 M
9
Solutions

• What is the boiling point of a solution that
  contains 4.6 moles of KBr in 1500 g of water? (Kb
  0.512?C/ m gram formula mass of water 18 g)

?T kbmn ?T (0.512)(4.6mol/1.5kg)(2) 103.1 oC
10
Soltions

• What is the freezing point of a solution of 0.80
  mol of LiBr in 850 mL of water? (Kf 1.86?C/m)

-3.5 oC
11
Equilibrium

• What is the expression for Keq for this
  reaction? 2H2O(g) ? 2H2(g) O2(g)

12
Equilibrium

• Calculate the equilibrium constant for the
  production of MgO when the equilibrium
  concentrations are 0.030M of Mg, 0.020M for O2,
  and 2.0 M for MgO?

13
Equilibrium

• In an endothermic reaction at equilibrium,
  what is the effect of lowering the temperature?

The system will shift toward to reactants (to the
left) and more reactants will be made.
14
Equilibrium

• What is the effect of adding more hydrogen gas in
  the following equilibrium reaction?
• C2H2(g) H2(g) ? C2H4(g)

More products will be made (the system will
shift right)
15
Equilibrium

• How does a decrease in pressure affect the
  following reaction?
• C2H2(g) H2(g) ? C2H4(g)

The system will shift towards the left (or the
reactants)
16
Thermo

• What does entropy measure?

The amount of chaos (disorder) in a system
17
Thermo

• What physical state of carbon dioxide has the
  highest entropy (solid, liquid, or gas)?

GAS
18
Acids Bases

• When an acid reacts with a base, what two types
  of compounds are formed?

Salt and Water
19
Acids Bases

• If the H in a solution is 1 x 10-1 mol/L, what
  is the OH-?

1x10-13mol/L
20
Acids Bases

• If the pH is 4, what is the concentration of
  hydrogen ion?

1x10-4M
21
Acids Bases

• What is an acid according to Arrhenius?

Gives off hydrogen ions in solution
22
Acids Bases

• What characterizes a strong acid or base?

Dissociates completely in water
23
Acids Bases

• What is the concentration in normals of sulfuric
  acid if 34.5 mL of acid is neutralized by 20.0 mL
  of 1.0 M sodium hydroxide?

0.58 N
24
Acids Bases

• What does a buffer do?

A buffer helps keep the pH of a solution stable
25
Thermo

• How much heat is absorbed by a 15.5 g piece of
  gold as it is heated from 4.5C to 177.4C? (the
  specific heat of gold is 0.129 J/gC)

q mc?t q (15.5g)(0.129 J/gC)(172.9 C) q
346 J
26
Thermo

• How much energy is needed to heat 164.5 g ice at
  -27.6oC to 0.00oC?

9,490 J
27
Nuclear

• 1. The half-life of radon-222 is four days.
  After how many days is the amount of radon-222
  one-eighth of its original amount?

12 days
28
Nuclear

• 1. What particle is needed to complete this
  nuclear reaction?

29
Nuclear
What particle is needed to complete this reaction?
30
Nuclear

• A piece of wood found in an ancient burial mound
  contains only one-fourth as much carbon-14 as a
  piece of wood cut from a living tree growing
  nearby. If the half-life (t1/2) for carbon-14 is
  5730 years, what is the approximate age of the
  ancient wood?

11,500 years
31
Nuclear

• Nitrogen-13 decays to carbon-13 with a half-life
  of 10.0 minutes. Assume that you are given a
  starting mass of 2.00 grams of nitrogen-13. How
  many grams of nitrogen-13 will remain after 42.7
  minutes?

0.104 grams
32
Final Jeopardy is next

• Teams, place your bets
• You may bet between 0 pts - max points you have.
• Each team will need to write down their final
  answer and bring it up for the judges to score.
• You have as much time as you need (within reason)

33
Final Jeopardy

• How much energy is needed to heat a 42.3 g sample
  of ice at 35.7C to steam at 112.0C?

132 kJ