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It's just some random substance in the air that catalyses it. Don't know what the specific name is, I think i can just put catalyst for this equation..

Which ones are best to use for HSC: SO2 contributing to acid rain: SO2 (g) + H2O (l) -> H2SO3 (aq) 2H2SO3 (aq) + O2 (g) -(catalyst above arrow)> 2H2SO4 (aq) OR 2SO2 (g) + O2 (g) -> 2SO3 (g) SO3 (g) + H2O (l) <-> H2SO4 (aq) Which set is better if I don't want to write 4...

re: HSC Chemistry Marathon Archive Yeah, if the reactants and products are all gases in a closed system, by adding a solid, you are decreasing the volume of the system, hence an increase in pressure and causing the equilibrium to shift to the side with less moles of gas.

For Question 26(c), Will it be alright if we used 14 = pH + pOH to calculate the pH. Because then, instead of working out the concentration of excess H+, we go straight to the answer, and so we skip a step which was worth 1 mark. Working out would just be (after the Concentration of excess...

For 12, you arrange the metals in order of most reactive to least (decreasing order) The numbers are their standard reduction potentials (given in question) So similarly to the reduction potentials on the back of the periodic table, the most negative is the most reactive, apply the same concept...

Oh right, got a bad habit of using all information if I get it, regardless if its necessary or not. Thanks. How about 20? Question is: "Which of the following can be used to help reduce SO2 emissions from factories?" A) CH3COOH B) Mg(OH)2 C) NH4Cl D) Na Is it something to do with being basic...

Need help with Question 12 because multiple choice doesn't give explanations. "5mL of 0.1M HCl is diluted to 100mL with water. What is the new pH of the solution?" A) 1.0 B) 2.3 C) 4.6 D) 5.3 Answer says B. but isn't the original solution a pH of -log(0.005 x 0.1) = 3.3 So how can diluting...

Nice, going to take a look (:

What's the equations? Since bromine water can be written as Br2 or BrOH, which one do we use? and when it decolourises, e.g. with hexene, is it: C6H12(l) + Br2(aq) --> C6H12Br2(aq) What is the equation with BrOH, since I only learnt the Br2 one.

When you write your galvanic cell in that format, what part correlates to which one? I forgot.

I feel that if Le Chatelier's comes up in the core section of the exam, it'll give an advantage for students who do Industrial chem since they learn it again in the option, and go more in depth. Does any other option give this kind of advantage?

I don't really get the question as the choice of solution in a salt bridge is important, because it can precipitate with the electrolyte in either half-cell, which screws up the system. So a proper solution for salt bridge is necessary which it must not cause precipitation, like potassium...

re: HSC Chemistry Marathon Archive Is this also a reasonable explanation? Since adding an acidic solution caused the indicator to change from yellow to red, adding a basic substance/alkaline solution will change it back. Sodium acetate is basic, as it is produced from strong base (NaOH) and...

re: HSC Chemistry Marathon Archive Will Copper metal dissolve in 1.0 M HCl (aq)? Give your reasions for why or why not.

Practise questions, that way you can grasp a better understanding of what you can and cannot answer. If you do not know how to answer a question, you can still go back and revise necessary content. Just going through the book right now alone, you might cover stuff you already know, and waste a...

re: HSC Chemistry Marathon Archive I'm pretty sure that since there is 2L of both SO2 and H2S, and they have different molar ratios, H2S becomes the limiting reagent. There would be 0.044 moles of SO2 leftover because 0.088 moles of H2S and 0.044 moles of SO2 is used up in the reaction...

re: HSC Chemistry Marathon Archive His answer is wrong. He made a mistake on that step that you bolded. Shoulda been: initial amount (using n=cV) was 0.250 x 0.05 = 0.0125 mol final amount = 0.0125 - 5.114x10^-3 = 7.386x10^-3 mol therefore final concentration =...

re: HSC Chemistry Marathon Archive There are Ca2P2O7 So Percentage of Phosphorus in Ca2P2O7 = Molar mass of phosphorus/Molar mass of Ca2P2O7 = (30.97x2/254.1) x 100, which gives 24.38%. So 24.38% of 0.232(precipitate) is phosphorus, which is 0.0566g. Mass of phosphorus/Mass of...

Dang, didn't know that, lost a mark already.

Doesn't Fax machine use binary, so its 0s and 1s. Which is the first answer (A) cause it only does 1 up or 0. I thought D was digital..