Mass
Can
[Start]
(g)
|
Mass Open Can
[5 days]
(g)
|
Mass Empty Can
(g)
|
Mass Control [Start]
(g)
|
Mass Control
[5 days]
(g)
|
418.26
|
414.01
|
16.28
|
382.82
|
379.01
|
414.21
|
411.25
|
16.69
|
405.42
|
403.03
|
416.12
|
413.42
|
16.54
|
405.42
|
403.03
|
409.77
|
406.01
|
16.21
|
405.55
|
402.27
|
419.36
|
416.65
|
16.48
|
391.2
|
389.02
|
413.93
|
409.88
|
15.9
|
380.25
|
377.93
|
418.36
|
414.82
|
15.91
|
389.64
|
386.98
|
WORKSHEET FEEDBACK – some good work
Q1d) You do not need the same amounts of products and reactants. Equilibrium can occur with any given ratio of products and reactants BUT at equilibrium the concentration of these products and reactants stays constant and the rate of forward and reverse reaction is constant
Q1i) First saying left or right is meaningless without an equation. Secondly if an exothermic reaction is heated the reverse or endothermic reaction is favoured as by LCP that endothermic reaction will act to absorb the heat and thus minimise the change in temperature.
Q1j) Read the whole Q very carefully.
Q1j) Read the whole Q very carefully.
Q2) If you made mistakes here you need to go back and revise LCP – you should be getting all these right now. Check 3c – are there really equal moles of gas on both sides?...
Q3) If the question says explain then you have to give the answer AND GIVE REASONS
Q3) All means P, V and adding/removing chemicals (cant use Temp as no DH data given)
Q3) All means P, V and adding/removing chemicals (cant use Temp as no DH data given)
Q5) When graphing the IV goes on the X-axis and the DV on the Y (ie temp on X). You should mark on your graph any interpolated (within your data) and extrapolated (beyond your data) values. If the data points make a clear curve USE A CURVE OF BEST FIT. DRAW THE LINE, SHOW WOKRING ON GRAPH. If we hadn't done it before I would understand but not including this stuff is just sloppy and lazy. I can show you how to succeed in Chemistry, I can encourage you to do your best but if you can't be bothered...
Q6) Bizarre question - but even still – you have to explain your answers by referring to LCP!
HSC Q - Ranged from outstanding to not
Q9 - Catalysts do not change equilibrium thus LCP is not related to catalysts - see Q24 below
Q10 - Read the equations VERY carefully
Q23b - SIG FIG...
Q9 - LIM EXCESS Q - check before solving
Q15 - This was in your assessment. You need to do those assessment Q again and again until they are second nature. The mole Q in the HSC get harder every year (ER become MC etc) and you need to be ready
Q18 - This equilibrium contains H+ - thus any acidic or basic chemical will affect the position of equilibrium
Q19 - If there is an equation you must use the mole ratio
Q23 - You must get the solubility right and you must relate to LCP. This was the WHOLE point of the experiment. What does it mean if you got it wrong? I don't have an answer. I don't understand.
Q14 - Writ a reaction equation and USE THE MOLE RATIO
Q24 - Catalyts do NOT affect the position of equilibrium. This I what we covered in 9.3.2. The sulfuric acid in esterification is an exception. You are taught it is an exception in 9.3.5. This exception I supposed to help you to remember that NORMALLY they DON'T affect equilibrium.
Q25 - You have to illustrate the equilibrium mixture with an equation. Indicators were taught as a specific example of equilibrium in 9.3.2
HSC Q - Ranged from outstanding to not
Q9 - Catalysts do not change equilibrium thus LCP is not related to catalysts - see Q24 below
Q10 - Read the equations VERY carefully
Q23b - SIG FIG...
Q9 - LIM EXCESS Q - check before solving
Q15 - This was in your assessment. You need to do those assessment Q again and again until they are second nature. The mole Q in the HSC get harder every year (ER become MC etc) and you need to be ready
Q18 - This equilibrium contains H+ - thus any acidic or basic chemical will affect the position of equilibrium
Q19 - If there is an equation you must use the mole ratio
Q23 - You must get the solubility right and you must relate to LCP. This was the WHOLE point of the experiment. What does it mean if you got it wrong? I don't have an answer. I don't understand.
Q14 - Writ a reaction equation and USE THE MOLE RATIO
Q24 - Catalyts do NOT affect the position of equilibrium. This I what we covered in 9.3.2. The sulfuric acid in esterification is an exception. You are taught it is an exception in 9.3.5. This exception I supposed to help you to remember that NORMALLY they DON'T affect equilibrium.
Q25 - You have to illustrate the equilibrium mixture with an equation. Indicators were taught as a specific example of equilibrium in 9.3.2
SUMMARY FEEDBACK – NB if you need space only include YOUR results
A) What visual observation led you to conclude that gas was released
B) To find the mass of CO2 we need to take the mass loss of the soft drink can (CO2 + water loss) and minus the control mass loss (water loss)
C) Concentration is moles per litre (c=n/V) – ie moles of dissolved CO2 per litre of solution. Remember that a soft drink can is 375ml!
D) The control increased the validity of the experiment. But WHY did measuring the water loss make it more valid? – i) you have to define validity ii) you had to note that we are measuring CO2 content by the mass loss of the can, iii) thus we had to ensure that the value we used for mass loss was for CO2 only – ie we had to determine and subtract any mass loss due to water else we would get an invalid overestimate.
E) When assessing you need to introduce the topic (Ie define reliability), address the +ves (eg repetition) address the –ves (ie different drinks, variations in results), and make a judgement. But to assess something is reliable you really need to compare the volumes of CO2 that each group calculated to see if there was consistency– did you do that? If not why not? What are you waiting for?
F) If you are discussing the impact of changing conditions on an equilibrium reaction you have to i) give the equation, ii) define LCP, iii) say what factor you are changing iv) Explain via LCP which way that causes the equilibrium to shift
G) It is called a series of equilibriums because you can write:
CO2 (g) + H2O (l) ↔ H2CO3 (aq) ↔ H+(aq) + HCO3 -(aq) ↔ 2H+ (aq) + CO32-(aq) DH -ve
H) You need to consider the following factors: temperature, pressure, volume, CO2 concentration, H+ concentration, CO32- concentration.
I) You need to consider all the above when explaining our choice and you need to say what is wrong with each of them – not just that the one we chose (decreasing pressure / increasing volume) was the ‘easiest’ – NB each of the other techniques has a considerable downside. Eg lowering CO2 concentration of the atmosphere practically impossible. Eg adding H+ = safety, adding CO32- =invalidates the experiment…why?
J) As for ALL conclusions for quantitative experiments you need to answer the AIM and HYPOTHESIS in a quantitative manner – WHAT DID YOU FIND OUT!?
K) UNITS!!!!!!
L) Gas volumes – equal volumes of gas contain equal number of moles – or one mole of a gas occupies a set volume at a given temp and pressure (ie V = nMV) – did we use this concept to calculate the CO2 volume?
AWESOME NEWS
2) KINGDOM RUSH HAS BEEN GREENLIT FOR A RELEASE ON STEAM = EXTRA CAMPAIGN COMING SOON
3) KINGDOM RUSH 2 IS IN PRODUCTION!!!
YES YES YES!!!
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