Reversibility of Reactions
What is the term for the number used to determine whether or not a given reaction is reversible, and its standard unit?
Gibbs Free Energy, and kJ/mol
What is Le Chatelier's Principle?
When a system at equilibrium is disturbed, the equilibrium will shift so as to minimise the disturbance.
What is the general form of the expression for the equilibrium constant?
Concentration of products over concentration of reactants, each individually raised to their stoichiometric coefficients.
What is the term given for the technique used by Aboriginal and Torres Strait Islanders to detoxify the cycad fruit using water?
Leaching.
What was my scaled HSC mark for chemistry?
Everyone guesses, closest gets the points!
89
What is the sign of enthalpy and entropy at SLC for the photosynthesis reaction?
Enthalpy is positive and entropy is negative.
What are two possible 'disturbances' that can be imposed on an equilibrium system?
Change in volume
Temperature Change
Addition of a reactant/product
Removal of a reactant/product
What is the equilibrium constant expression for this reaction?
NH3(aq) + H2O(l) <-> NH4+(aq) + OH-(aq)
[NH4+] [OH-] / [NH3]
If the concentration of sodium ions in a solution of salt water is 6.13M, what is the Ksp of sodium chloride at this temperature?
37.6
What are the names of the two degrees I am studying, with the correct majors?
100 points per correct answer.
Bachelor of Science (Maths/Chem Double Major)
Masters of Secondary Education
What is the name of the reaction that is the reverse of photosynthesis?
What are the possible changes that could be imposed on the following equilibrium reaction in order to decrease the yield? 100 points per answer.
Fe3+(aq) + SCN-(aq) <-> FeSCN2+(aq)
Adding water
Increasing the amount of product present
Removing reactant ions from the solution
Nitrosyl bromide decomposes according to the equation shown below. A 0.64 mol sample of NOBr is placed in a 1L flask. After the system comes to equilibrium, the flask contains 0.46 moles of NOBr. What is the value of Keq for this reaction?
2NOBr(g) <-> 2NO(g) + Br2(g)
0.014 (2sf)
What is the Ksp threshold that must be met in order to use the 'small change assumption' to simplify questions, in order to avoid using the quadratic formula?
Must be less than 1x10-3
To the nearest day, how many days worth of music did I listen to this year?
Everyone guesses, closest gets the points!
21 days (30,875 minutes specifically)
There are two different forms of the cobalt (II) chloride salt in ionic form, depending on the equilibrium reaction studied at the beginning of this module. What are the ionic forms (with correct charge) and what are their colours?
100 points per ionic form, 100 points per matching colour
[Co(H2O)6]2+(aq) is a red/pink colour, and [CoCl4]2-(aq) is a blue colour.
Hydrogen and iodine gas can combine to form an equilibrium with hydrogen iodide gas. Hydrogen and hydrogen iodine gas are colourless, whereas iodine gas is a deep purple colour. If a vessel containing all 3 gases above has its volume doubled, what is the perceived change in intensity of the purple colour?
No change! The chemical reaction is:
H2(g) + I2(g) <-> 2HI(g)
Since there are two moles of gas on both sides of the reaction, changing the volume has no affect on the equilibrium, as the concentrations all change equally, having no effect on Keq!
In a 10L reaction vessel, there are 4.50 moles of nitrogen gas, 1.00 mole of hydrogen gas, and 5.80 moles of ammonia gas at equilibrium. At this temperature, the value of Keq is 458. How many moles of nitrogen gas need to be added to the vessel to increase the amount of ammonia present by 0.050 moles?
1.31 moles.
What are the ions that are typically insoluble, but not included in the NAG-SAG/PMS/Castro Bear acronyms and mnemonics?
100 points per ion.
Hydroxides, Carbonates, Phosphates, and Sulfides.
What is my personal ranking of the 4 different year 12 chemistry modules?
Each person gets to make their ranking, and everyone will receive 100 points per correctly placed module.
1. Module 7 (Organic Chemistry)
2. Module 8 (Applying Chemical Ideas)
3. Module 5 (Equilibrium Reactions)
4. Module 6 (Acid & Base Reactions)
What must the sign of entropy and enthalpy be for a reaction in order for only the reverse reaction to occur spontaneously at only low temperatures?
Both must be positive.
What is the reason that if a glass of water and a bottle of water are left out, only the glass of water will have a noticeable change in taste?
The glass exists as an open system and can never reach equilibrium, whereas the bottle is sealed and thus a closed system, meaning it can establish the following equilibrium and has minimal carbonic acid form:
CO2(g) + H2O(l) <-> H2CO3(aq)
When an aqueous solution of bromoacetic acid (BrCH2COOH) is shaken with octan-1-ol, an equilibrium is established between bromoacetic acid dissolved in water and the octan-1-ol:
BrCH2COOH(aq) <-> BrCH2COOH(octan-1-ol)
Bromoacetic acid cannot ionise in octan-1-ol, but can in water, according to the following equation:
BrCH2COOH(aq) <-> H+(aq) + BrCH2COO-(aq) (Ka = 9.18x10-3)
An aqueous solution of bromoacetic acid with an initial concentration of 0.1000M is shaken with an equal volume of octan-1-ol. When the system reaches equilibrium, [H+] = 9.18x10-3 M. What is the Keq for the octan-1-ol and water system?
0.390
The following three solids were added to 1L of water: 0.006 moles magnesium nitrate, 0.010 moles sodium hydroxide, and 0.002 moles sodium carbonate. Which precipitates, if any, will form? Must have calculations to get the points!
Magnesium Hydroxide will precipitate out.
Beyond my own personal rating, what are the 5 categories I rank board games on?
100 points per correct answer.
Ease of Learning
Ease of Playing
Speed of Gameplay
Repeatability
Originality