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Weak acids are usually used as indicators because they will partly dissociate when dissolved in an acid or base. This is the dissociation equation for HIn which is a commonly used indicator. HIn + H2O <=> H3O+ + In- If you dissolve this in an acid for example, according to Le Chatelier's...

I'll be honest, my chemistry is quite rusty but I'll give it a go, so take this with a grain of salt (someone please correct me if any of my answers are wrong) 1. You want to increase [HOCl] by favouring the forward reaction and shifting equilibrium to the right. Out of all the options, HCl is...

Trial HSC varies for every high school but usually covers all topics that you've learnt up to at school. Actual HSC covers everything in the syllabus. There are no dumb questions, always ask if you're unsure about anything!

Correct, sig figs work a bit differently for logs. For a log, the number of sig figs is based on its decimal component (i.e. 0.22). Therefore, a pH of 5.22 would have 2 sig figs based on its decimal component. Keep this in mind whenever you're calculating pH, same rule applies when finding [H+]...

No worries, glad to hear!

They're used for finding equilibrium constants (K) when you don't have sufficient information to calculate K directly using the formula. You'll usually need to use it when the question gives you a chemical equation and some small bits of information such as initial moles or concentration, but...

I mean I don't function even after 10 hours of sleep because I fall asleep in all my classes anyway but that's just me

You never multiply the cell potential, only multiply whatever is in the half equation when your trying to make a full equation from the two half equations, which you don’t need to in this q anyway

My chemistry knowledge is a bit rusty, but hopefully this makes sense. By calculating the oxidation numbers of Cr and Fe in the equation, you should see that Cr goes from a charge of 6+ to 3+ while Fe goes from charge 2+ to 3+, meaning that Cr is gaining electrons and therefore undergoing...

Engineer, I thought commerce would be useful for having a degree in any situation but apparently that's not the case Now I understand most people do engineering and commerce because they are still unsure of what they want to do after uni

Right, so if I was certain in doing engineering would commerce be kind of useless to study? Thanks for the reply

Hi, I'm currently doing electrical engineering (BE/ME) at UNSW, but I'm not sure if I should continue with this or transfer to a dual degree in electrical engineering and commerce. Would a master's degree or double degree be better in this case for job prospects and what sort of jobs am I more...

Ayyy same here! Did you do AMEB grades in classical before you learnt acoustic and electric too?

Your working out solves the area below y=e^-x, you need to find the area bounded between y=1 and y=e^-x

A and B produce CO2 which is complete combustion (Carbon soot/carbon monoxide is produced from incomplete combustion). D is incorrect because oxygen isn't balanced on both sides. Therefore the only correct answer is C

Here is my working out https://i.imgur.com/4UKZC6m.jpg You need to use the fact that when x=0, f'(x)=0 too, as given where it says f(x) is horizontal as it passes through the origin

b) https://i.imgur.com/89enlCf.jpg

14a) https://i.imgur.com/3iLSnxN.jpg

Re: 2017 HSC Marks Thread 3u maths: 90 4u maths: 85 chemistry: 87 physics: 87 english adv: 70 being super harsh on myself so i don't get my hopes up lol, can't believe i can still get into (most) unsw engineering courses (over 92) with those marks when i put them into an atar calculator

You don't need to, the velocity of all electromagnetic waves will be 3x10^8 regardless, since microwaves are a type of EMW the answers to both parts are basically the speed of light, doesn't matter which direction the spaceship is travelling or what it's relative to