HSC Chemistry Question Thread

[conic curve]

For every 10 marks, you need to successfully gain 9 of them.

This would require constant study, to the detriment of most of your other subjects, and discipline beyond that of most human beings. I would never be aiming for a raw mark of 90; it's not unachievable, but it's pretty damn tough.

Basically, to get the absolute best atar you can, you need to try consistently hard throughout the year, and do the best you can. Don't aim for a particular mark, except maybe to match/beat your previous mark. You could get raw marks of 60 throughout the year and still get a 99.95 Atar. So don't worry about marks; just try, try and try again.

Jake

Thanks for inspiration Jake 

[anotherworld2b]

Hi i was wondering if i could get help with q7

[jakesilove]

Hi i was wondering if i could get help with q7

Hey! So, at each of the times specified, you need to draw a straight line tangential to the graph. Tangential just means with the same gradient, so it should just touch the graph once. Then, you need to find the gradient of that graph; to do this, choose two points on the line, and use the gradient formula!

Jake

[conic curve]

In year 12, do you do a chemistry prac on dilution? If so which module is it in?

BTW Jake, I think I asked you this before but do you study chemistry at uni?

[jakesilove]

In year 12, do you do a chemistry prac on dilution? If so which module is it in?

BTW Jake, I think I asked you this before but do you study chemistry at uni?

No, you don't. However, maths questions can ask you to utilise



I studied Chem in the first semester of my first year, but not beyond that.

[conic curve]

No, you don't. However, maths questions can ask you to utilise



I studied Chem in the first semester of my first year, but not beyond that.

Was it chem that was related to the HSC (i.e. they teach you concepts from the HSC which builds up in uni)

[karenc.]

In year 12, do you do a chemistry prac on dilution? If so which module is it in?

BTW Jake, I think I asked you this before but do you study chemistry at uni?

no it's part of the year 11 water topic

[jakesilove]

Was it chem that was related to the HSC (i.e. they teach you concepts from the HSC which builds up in uni)

No, university Chemistry is nothing at all like HSC chem.

[massive]

how do you do this?

What is the pH if 1 litre of hydrogen chloride gas at STP is dissolved in 1.2 litres of pure water?

[RuiAce]

how do you do this?

What is the pH if 1 litre of hydrogen chloride gas at STP is dissolved in 1.2 litres of pure water?

Try converting the volume of gas into moles of gas using n = V/V_m

V_m = 24.79 L mol^-1 at STP from the data sheet


Then you can just C=n/V it to get your required concentration(s)

[wesadora]

Try converting the volume of gas into moles of gas using n = V/V_m

V_m = 24.79 L mol^-1 at STP from the data sheet


Then you can just C=n/V it to get your required concentration(s)

is final V in c=n/v 2.2L or 1.2L?

[RuiAce]

is final V in c=n/v 2.2L or 1.2L?

You don't use final V.

You use V = volume of water. Not V = volume of solution.

Because concentration is a measure of quantity of a substance with respect to an environment. We only consider the "changed" environment for FURTHER disturbances.

[anotherworld2b]

For these two questions what would be necessary to include to get full marks?

[jakesilove]

For these two questions what would be necessary to include to get full marks?

Hey!

For your first question, I would say something like this. Neutralization will occur when equal amounts of Hydroxide and Hydrogen ions are present in solution. If you are titrating a strong acid/strong base, this will be around a pH of 7. If you are titrating a weak acid/strong base etc. etc. etc. A pH indicator can be selected so that it's end point is near the desired pH. When the colour changes, the desired pH has been reached, and thus the equivalence point is at approximately this point.

For your second question, note that the equivalence point is the point at which there are equal moles of -OH and H in the solution, whilst the end point is the point at which the indicator changes colour. These might not be precisely the same, leading to errors in the experiment.

Jake

[massive]

What would be the answer to the following question:

Which of the following does NOT usually occur during the cracking of high boiling fractions of crude oil?
A) a decrease in the pressure of the reaction vessel
B) the formation of products with a higher total chemical potential energy than the reactants
C) the production of smaller saturated hydrocarbons
D) the formation of unsaturated hydrocarbons