North of Sepo - new forum threads http://northofsepo.wikidot.com/forum/start Threads in forums of the site "North of Sepo" - ... where education rocks! Wed, 16 May 2012 23:36:58 +0000 http://northofsepo.wikidot.com/forum/t-468422 Surds - Year 10 http://northofsepo.wikidot.com/forum/t-468422/surds-year-10 Mon, 14 May 2012 12:31:25 +0000 Wes Prosser 276877 Ask questions here about surds!

]]> http://northofsepo.wikidot.com/forum/t-457114 Thank you! http://northofsepo.wikidot.com/forum/t-457114/thank-you Thu, 29 Mar 2012 03:52:58 +0000 Da Man 1192098 Hey Wes!
Just wanted to say a big thanks for your help! I did the test on saturday just gone and it went pretty well! So i am hopeful that this year will be the year :D Thanks for helping me grasp topics i have been struggling with! Next time i am down we will have to catch up so i can say thanks in person :D

]]> http://northofsepo.wikidot.com/forum/t-447285 Chemical Thermodynamics http://northofsepo.wikidot.com/forum/t-447285/chemical-thermodynamics Questions from Worksheet 5 (Jan 2012) Sat, 03 Mar 2012 04:02:26 +0000 Wes Prosser 276877 Q 8.65 A system absorbs 300 J heat and has 700 J of work done on it. What is ΔU? Is this overall endothermic or exothermic?

ΔU = +300 J + +700J = +1000 J ✓
System is endothermic as it has absorbed heat. ✓

]]> http://northofsepo.wikidot.com/forum/t-446978 Chemical Reactions and Stoichiometry http://northofsepo.wikidot.com/forum/t-446978/chemical-reactions-and-stoichiometry Questions from Worksheets 3 & 4 (Jan 2012) Fri, 02 Mar 2012 10:53:36 +0000 Wes Prosser 276877 Q 3.30 Balance the following equations:
(a) Ca(OH)2 + HCl → CaCl2 + H2O
(b) AgNO3 + CaCl2 → Ca(NO3)2 + AgCl
(c) Fe2O3 + C → Fe + CO2
(d) NaHCO3 + H2SO4 → Na2SO4 + H2O + CO2
(e) C4H10 + O2 → CO2 + H2O

(a) Ca(OH)2 + 2HCl → CaCl2 + 2H2O ✓
(b) 2AgNO3 + CaCl2 → Ca(NO3)2 + 2AgCl ✓
(c) 2Fe2O3 + 3C → 4Fe + 3CO2 ✓
(d) 2NaHCO3 + H2SO4 → Na2SO4 + 2H2O + 2CO2 ✓
(e) C4H10 + 6½O2 → 4CO2 + 5H2O
∴ 2C4H10 + 13O2 → 8CO2 + 10H2O

]]> http://northofsepo.wikidot.com/forum/t-446967 Language of Chemistry http://northofsepo.wikidot.com/forum/t-446967/language-of-chemistry Questions from Worksheet 2 (Jan 2012) Fri, 02 Mar 2012 09:52:31 +0000 Wes Prosser 276877 Q 2.44 Name the family to which each compound belongs.
(a) CH3CH=CH2
(b) CH3CH2CH2COOH
(c) CH3CH2OH
(d) HOCH2CH2CH3

(a) Has a C=C (carbon-carbon double bond), therefore is an Alkene. ✓
(b) Has a -COOH (carboxyl group), therefore is a Carboxylic Acid.
(c) Has a -OH (hydroxyl group), therefore is an Alcohol. ✓
(d) Has a -OH (hydroxyl group), therefore is an Alcohol. ✓

]]> http://northofsepo.wikidot.com/forum/t-446966 Mass Ratio http://northofsepo.wikidot.com/forum/t-446966/mass-ratio Questions from Worksheet 1 (Jan 2012) Fri, 02 Mar 2012 09:39:11 +0000 Wes Prosser 276877 Q 1.35 Laughing gas has 1.75g of Nitrogen for every 1g of Oxygen. Which is laughing gas?
(a) 6.35g N, 7.26g O
(b) 4.63g N, 10.58g O
(c) 8.84g N, 5.05g O
(d) 9.62g N, 16.5g O
(e) 14.3g N, 40.0g O

(a) 6.35g N : 7.26g O = 0.875g N : 1.00g O
(b) 4.63g N : 10.58g O = 0.438g N : 1.00g O
(c) 8.84g N : 5.05g O = 1.75g N : 1.00g O
(d) 9.62g N : 16.5g O = 0.583g N : 1.00g O
(e) 14.3g N : 40.0g O = 0.358g N : 1.00g O
Therefore (c) is the correct answer.

✓ As you mention, m(N) needs to be bigger than m(O), so you can quickly jump to the correct answer.

]]> http://northofsepo.wikidot.com/forum/t-414607 Topics to talk about http://northofsepo.wikidot.com/forum/t-414607/topics-to-talk-about Wed, 23 Nov 2011 10:15:09 +0000 Da Man 1192098 This is a thread for me to list topics that we might need to discuss due to difficulty in the concept etc:
Atomic and hybrid orbitals

]]> http://northofsepo.wikidot.com/forum/t-401598 Calculations using exponentials and logs http://northofsepo.wikidot.com/forum/t-401598/calculations-using-exponentials-and-logs Mon, 17 Oct 2011 10:02:08 +0000 Da Man 1192098 Wes!
I have started doing Acid/base questions and getting into pH. One issue i currently have is i have no idea how to do exponential and log calculations on a standard scientific calculator. Is you able to help?

example of a expo q is 1.0 x 10^-14/4.4 x 10^-8 kind of thing. The majority of the pH questions i am guessing are -log's as well

Hope your well and work has settled down a little!

]]> http://northofsepo.wikidot.com/forum/t-390927 Empirical Formula http://northofsepo.wikidot.com/forum/t-390927/empirical-formula Thu, 15 Sep 2011 04:00:13 +0000 Wes Prosser 276877 Q: A white powder has %mass of Ba 69.6%, C 6.09% and O 24.3%. What is the empirical formula? (M(Ba) = 137.3 g mol-1, M(C) = 12.01 g mol-1, M(O) = 16.00 g mol-1)
(Worksheet 6)

In a 100 g sample, m(Ba) = 69.6 g, m(C) = 6.09g, and m(O) = 24.3 g
n(Ba) = m(Ba) ÷ M(Ba) = 69.6 ÷ 137.3 = 0.507 mol
n(C) = m(C) ÷ M(C) = 6.09 ÷ 12.01 = 0.507 mol
n(O) = m(O) ÷ M(O) = 24.3 ÷ 16.00 = 1.52 mol
Mole ratio is 0.507 : 0.507 : 1.52 = $\frac{0.507}{0.507} : \frac{0.507}{0.507} : \frac{1.52}{0.507}$ = 1 : 1 : 3
Therefore, the empirical formula is BaCO3

✓ Total blitz!

]]> http://northofsepo.wikidot.com/forum/t-390918 Find Mass http://northofsepo.wikidot.com/forum/t-390918/find-mass Thu, 15 Sep 2011 03:08:02 +0000 Wes Prosser 276877 Q: If a procedure can deposit 0.115 mol of pure Ca3(PO4)2 on an implant, what is the mass of the coating? Molar mass of Ca is 40.08 g mol-1, of P is 30.97 g mol-1 and of O is 16.00 g mol-1.
(Worksheet 1)

M(Ca3(PO4)2) = 3 × 40.08 + 2 × 30.97 + 8 × 16.00 = 310.2 g mol-1
m = M × n = 310.2 × 0.115 = 35.7 g

✓ All good!

]]> http://northofsepo.wikidot.com/forum/t-390375 Find Moles http://northofsepo.wikidot.com/forum/t-390375/find-moles Tue, 13 Sep 2011 22:42:12 +0000 Wes Prosser 276877 Q: A stone has a mass of 109.13g, and is made of pure carbon. Carbon has a molar mass of 12.01 g mol-1. What is the amount of C?
(Worksheet 1)

n = m ÷ M = 109.13 g ÷ 12.01 g mol-1 = 9.087 mol

✓ All good!

]]> http://northofsepo.wikidot.com/forum/t-390359 Percentage Mass http://northofsepo.wikidot.com/forum/t-390359/percentage-mass Tue, 13 Sep 2011 22:30:14 +0000 Wes Prosser 276877 Q: A sample of hydrocarbon of mass 8.657 g has composition of 5.217 g of C, 0.9620 g H and 2.478 g of O. What is the % composition?
(Worksheet 4)

% by mass is:
%m(C) = m ÷ m = 5.217 ÷ 8.657 × 100 = 60.25%
%m(H) = m ÷ m = 0.962 ÷ 8.657 × 100 = 11.11%
%m(O) = m ÷ m = 2.478 ÷ 8.657 × 100 = 28.62%

✓ Yep all good. Although, the question should specify % composition by mass, 'cos you could do % composition by molarity:

% by moles is:
n(C) = m ÷ M = 5.217 ÷ 12.01 = 0.4344 mol
n(H) = m ÷ M = 0.962 ÷ 1.008 = 0.9544 mol
n(O) = m ÷ M = 2.478 ÷ 16.00 = 0.1549 mol
%n(C) = 0.4344 ÷ (0.4344 + 0.9544 + 0.1549) × 100 = 28.14%
%n(H) = 0.9544 ÷ (0.4344 + 0.9544 + 0.1549) × 100 = 61.83%
%n(O) = 0.1549 ÷ (0.4344 + 0.9544 + 0.1549) × 100 = 10.03%

By mass is common, but not very useful from a chemical perspective. By moles is less common, but more useful. Bit twisted, hey?

]]> http://northofsepo.wikidot.com/forum/t-389939 Work Sheets http://northofsepo.wikidot.com/forum/t-389939/work-sheets Mon, 12 Sep 2011 10:35:11 +0000 Da Man 1192098 http://www.mediafire.com/?r55e4b8jbhno88n

Hey wes, these are the first set of work sheets. You able to check them out? :D

]]> http://northofsepo.wikidot.com/forum/t-388789 Text Books http://northofsepo.wikidot.com/forum/t-388789/text-books Text book discussion for self directed learning for GAMSAT Science Thu, 08 Sep 2011 09:15:54 +0000 Da Man 1192098 Hello All
Thought perhaps the best point to start would be discussion around text books/study material. Basically im utilising 3 books
1) The Gold standard GAMSAT -> commercially available GAMSAT prep book that i got of ebay. Covers all the major science topics in decent detail and helps provide good direction for study
2) Chemistry by Blackman et al (2008) -> a required text for 1st year chemistry students at UQ, has practice questions, worked examples etc and goes into subjects in a lot more detail. Used for cross referencing and to assisst in under standing topics that other books dont' explain well. Down side is has no answers for the questions (enter the Wes man)
3) Physics for Scientists and engineers 2nd edition by Knight. Used in the same way as Chemistry and same issues re answers.

Just wanting to see if anyone would suggest any other text books that they think are good, explain things wells etc

DaMan

]]> http://northofsepo.wikidot.com/forum/t-307828 Notes To Self http://northofsepo.wikidot.com/forum/t-307828/notes-to-self Mon, 14 Feb 2011 06:22:06 +0000 Wes Prosser 276877 Learning Goals:

  • "Understand the basic concepts of computer programming"
  • "Learn how to write programs for Turtle Graphics as a simple example of computer programming"

Performance Goals:

  • "Draw a square using Turtle Graphics"
]]>