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Q) Calculate the enthalpy change which occurs when 0.50 g magnesium is burned in air, 12.4 kJ of heat is released.

Q) Calculate the molar heat of the solution for ionic substances involved in the experiment which was carried out in well insulated plastic beakers using a thermometer which read to 0.1 C. Take the specific heat capacity of the fnal solutions as 4.2 J/k/g. 5.3 g calcium chloride was dissolved in...

Q1) How many moles of Hydrogen are needed to form 40 moles of ammonium? Q2) What mass of zinc is formed when 0.2 mole zinc oxide reacts with excess carbon? Q3) Copper is extracted from chalcocite (copper(1) sulfide) by roasting the ore in the air. When 15.3 g chalcocite was so treated, 11.3 g...

Do molecules which are made up of the same type of element' such as O2(Oxygen gas)' have the same valency as the individual element? For example does OS, N2 etc have the same valency as O and N respectively?

Go EDIT: When you name a metal, don't forget to state its valency there as well.

I'm just wondering if my procedure for writing a science practical report is correct. Aim Hypothesis Equipment Safety Issues Method Results Analysis Conclusion I have a feeling that I might be wrong somewhere.

Solve simultaneously: 2\leq\mid2x+3\mid\leq11

Okay I'm doing Trigonometric Equations and there a few symbols in my book that I don't get. sinx = sina x = a+2k \pi, \pi-a+2k \pi or x=(-1)^k a+k \pi, k \in J What's K and J? And what's that symbol that looks like a capital E mean? If it isn't too much trouble could you guys also...

Do you think that it is a good idea if I don't write up my own notes for Physics,Chemistry and Biology but instead use the ones on the resources section? I have separate notes for each of them but these summarise the text book and don't follow the dot points. Having notes based on the dot points...

Two of the roots of the equation x^3+ax^2+b=0 are reciprocals of each other. Show that a=b-1/b This is the only question in my homework that I don't get so any help will be greatly appreciated.

This book is a bit dodgy as it doesn't include all the formulas. I'm stuck on a couple of questions so I would appreciate any help. Q49) The space station Mir had a mass of 130 tonnes. It operated in a near circular orbit at altitude 480 km. Its centripetal force is 1.10 x 10^6 N. Calculate its...

I know this quite subjective but I just want to hear what other people have to say.

Some kids relax while others take out their books and revise. What do you guys do in the last few minutes till your test?

I've noticed that on the Board's website that all the descriptions of Band 6/E4 say that a student must be able to exhibit extensive knowledge. Does that mean that you need knowledge beyond the syllabus to get a mark in the top Band? Are their going to be questions in the HSC which require you...

I'm planning on self accelerating for Mathematics Extension 1. Unfortunately, I use Cambridge. It has good questions but very poor explanations so I was wondering if you guys could help explain to me some things which I don't understand. For definite integrals how are we supposed to know which...

I know that it might be a bit too early to ask this question and I know this might not be the right place to post this thread. I'm just wondering, from Physics, Chemistry and Biology which Optional Topic from each Science is the easiest?

I'm not the best at English so I wonder if there are any good books which could enhance your skills of the subject. I'm not talking about any Text Books or Study Guides but rather Story Books. Are there any good books that you guys could recommend which make an elaborate and vivid use of...