Final Jeopardy Subterm 2 Solutions* Equilibrium* Acids & Bases* Thermochemistry* Redox Nuclear Chemistry* Organic Chemistry

Calculate the H for this reaction: C2H4(g) + H2(g)  C2H6(g) THERMO Calculate the H for this reaction: C2H4(g) + H2(g)  C2H6(g) (H f for C2H4(g) = 52.5 kJ/mol; Hf for C2H6(g) = -84.7 kJ/mol)

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

What three operations makes a substance dissolve faster in a solvent? Solutions What three operations makes a substance dissolve faster in a solvent? Heating Agitation/stirring Smaller surface area/particle size

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? 5g/100g H20 20g/200g H20 25g/300g H20 55g/500g H20

Solutions What is the molarity of a solution that contains 6 moles of solute in 2 liters of solution? 6mol/2L = 3M

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

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

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

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

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

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?

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.

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)

How does a decrease in pressure affect the following reaction? 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)

Thermo What does entropy measure? The amount of chaos (disorder) in a system

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

Acids & Bases When an acid reacts with a base, what two types of compounds are formed? Salt and Water

Acids & Bases If the [H+] in a solution is 1 x 10-1 mol/L, what is the [OH-]? 1x10-13mol/L

Acids & Bases If the pH is 4, what is the concentration of hydrogen ion? 1x10-4M

Acids & Bases What is an acid according to Arrhenius? Gives off hydrogen ions in solution

Acids & Bases What characterizes a strong acid or base? Dissociates completely in water

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

Acids & Bases What does a buffer do? A buffer helps keep the pH of a solution stable

Thermo How much heat is absorbed by a 15.5 g piece of gold as it is heated from 4.5°C to 177.4°C? (the specific heat of gold is 0.129 J/g°C) q = mct q = (15.5g)(0.129 J/g°C)(172.9 °C) q = 346 J

Thermo How mcuh energy is needed to heat164.5 g ice at -27.6oC to 0.00oC? 9,490 J

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

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

Nuclear What particle is needed to complete this reaction?

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

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

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)

Final Jeopardy How much energy is needed to heat a 42.3 g sample of ice at –35.7°C to steam at 112.0°C? 132 kJ