Most imperative conceptsin 1/2 chemistry

[nacho]

Hi, just before I go on into 3/4 chem, i'd have to admit i screwed chem 1/2 so bad (averaging like 60%). So before starting unit 3, i was going to go over 1/2 again and was just wondering what the most important concepts are. (Obviously stoich) but do I need to know how to draw structures molecules and the types of bondings?
Could someone make a list..

Although being able to apply them, I never completely understood these definitions:

Relative Isotopic Mass - Is the mass of an atom of that isotope relative to the mass of an atom of 12C taken at 12 units exactly.
                                                                                                                                         
Mole - the amount of substance that contains the same number of specified particles as there are in 12 g of carbon-12.
                                                                                                                                   ^There are 6.02 x 10^23 right?

[taiga]

What is important:

Gas laws (pv=nrt)

Moles, how to calculate from the mass of something

volumetric analysis (i think you did this at the end of unit 2 ? )

solubility table (should be somewhere in your book)

cathodes/electrodes etc (only for unit 4)

some retaining of green chemistry helps along the process for energy sources in unit 4

[dptjandra]

Hi, just before I go on into 3/4 chem, i'd have to admit i screwed chem 1/2 so bad (averaging like 60%). So before starting unit 3, i was going to go over 1/2 again and was just wondering what the most important concepts are. (Obviously stoich) but do I need to know how to draw structures molecules and the types of bondings?
Could someone make a list..

Although being able to apply them, I never completely understood these definitions:

Relative Isotopic Mass - Is the mass of an atom of that isotope relative to the mass of an atom of 12C taken at 12 units exactly.
                                                                                                                                         
Mole - the amount of substance that contains the same number of specified particles as there are in 12 g of carbon-12.
                                                                                                                                   ^There are 6.02 x 10^23 right?

You do need to be able to draw molecular structures at the very least, and organic compounds with their different isotopes.

Relative isotopic mass means how much some isotope weighs in comparison to Carbon-12.  Carbon-12 is assigned 12 units exactly.  So if one atom of a certain element weighs twice as much as one atom of Carbon-12, then that element's relative isotopic mass is 2 x 12 = 24 mass units.

And yes, Avagadro's number is 6.02 x 10^23, which is the number of Carbon-12 atoms in a sample of 12g of Carbon-12 (also known as 1 mol)

I'll get out the Unit 1/2 book and see if I can write a quick list.

[dptjandra]

1. Understand the concept of discrete electron energy levels (don't need to memorise 1s2 2s2, etc.)
2. Understand the trends in the periodic table (eg. electronegativity across a period, down a group, etc.).  VITAL: stability of the octet (and how that affects reactivity)
3. Stoichiometry, as indicated.
4. Concept of the metal lattice (free electron system), ionic compounds (electrostatic attraction between ions greater than electrostatic repulsion) and covalent bonding (shared electrons)
5. The types of intramolecular bonds (covalent, permanent dipolar, hydrogen bonding).  Esp. application to water.
6. How to draw the valence structure of molecules (generally only need to draw with lines, not with dots and not anything 3D looking).  Some concept of spacing is good but not vital.
7. Hydrocarbons, esp. alkanes and alkenes --> drawing their isotopes, naming, appreciation of some of their chemistry (esp. combustion for alkanes/alkenes, and addition reactions for alkenes).
8. Understand the concept of a polymer (not all details needed)
9. Specific heat capacity - calculations and reasoning.
10. Understand WATER - its SHC, its various boiling/freezing points and the properties of the different states (understand how it acts as a solvent - as part of a wider understanding of why things dissolve...can be linked to the solubility table).  In contrast, why do some things then precipitate?
11. Stoichiometry regarding solutions.
12.  The concept of a Lowry-Bronsted Acid and Base.  Indicators, reactions they undertake, common strong and weak acids/bases, pH, etc. (almost all 1/2 acid-based work is important imo)
13. Limiting reagents.  In conjunction with or separately to volumetric analysis.
14. All redox and electrochem
15. Ideal gas behaviour (understanding of kinetic molecular theory is pretty helpful).  especially, PV = nRT and related stoich.
Sorry if this confuses you more - that's most of the stuff I used from 1/2 that I used in 3/4.

[luffy]

Into how much depth do you need to know those details though? Do we just need to remember the actual concept? Or is it best to remember exactly how to apply each of them?

I applaud this "nacho" for making such a thread. Nice work.

[nacho]

Thank you dptjandra, this will be very useful for my 1/2 revision over the course of the next few days.
Would you be able to recommend any study guides, or a second textbook for an extra resource?
At school we will use the Nelson chemistry textbook. I've no idea how good it will be because for year 11 we used Heinemann chemistry.
Thanks again.

[Greatness]

you should probably try getting heinamann chemistry 2 - just get the pdf

[dptjandra]

Into how much depth do you need to know those details though? Do we just need to remember the actual concept? Or is it best to remember exactly how to apply each of them?

I applaud this "nacho" for making such a thread. Nice work.

I would consider the things I've put on the list as pretty fundamental concepts in chemistry (that is, they're not things like "Different sources of energy" which you just need to memorise before an exam) - if you don't understand them to the depth covered in 1/2, you're lacking a really, really solid foundation (which I felt helped me in understanding 3/4 chemistry, and chemistry in university).  That said, it all depends how much time you want to invest in revising your chemistry.  If you don't want to spend so much time, you can just go through the Unit 3/4 book instead of the 1/2 book and you would probably be fine (could look at 1/2 book where necessary).

[Greatness]

dptjandra, what do you think is the most trickiest concept in Unit 3 chemistry or the concept where you should pay extra attnetion??

[dptjandra]

Thank you dptjandra, this will be very useful for my 1/2 revision over the course of the next few days.
Would you be able to recommend any study guides, or a second textbook for an extra resource?
At school we will use the Nelson chemistry textbook. I've no idea how good it will be because for year 11 we used Heinemann chemistry.
Thanks again.

I really like Heinemann.  I also looked through a text book which they use in university by Zumdahl, but that was more for personal interest than really a necessity for 3/4 chemistry.  None of the study guides have really, really impressed me tbh.

[dptjandra]

dptjandra, what do you think is the most trickiest concept in Unit 3 chemistry or the concept where you should pay extra attnetion??

In my view, probably electrochemistry and the real meaning/use of the electrochemical series.  That is really covered in Unit 4, though - of the material in Unit 3, make sure you understand acids and bases.

[Greatness]

dptjandra, what do you think is the most trickiest concept in Unit 3 chemistry or the concept where you should pay extra attnetion??

In my view, probably electrochemistry and the real meaning/use of the electrochemical series.  That is really covered in Unit 4, though - of the material in Unit 3, make sure you understand acids and bases.

thank you!!! well do we learn acid and bases in more detail than units 1/2?

[dptjandra]

Yeh - you do it with a lot of the analytical techniques (eg. titration), organic acids, and also taken further when you start to do problems involving equilibrium.

[Greatness]

sounds fun :p thanks again

[taiga]

Thank you dptjandra, this will be very useful for my 1/2 revision over the course of the next few days.
Would you be able to recommend any study guides, or a second textbook for an extra resource?
At school we will use the Nelson chemistry textbook. I've no idea how good it will be because for year 11 we used Heinemann chemistry.
Thanks again.

"A+ notes" are the best for chem in my opinion.

Has pretty much everything, the layout is nice which makes it good to read, and it's in relatively simple terms. Additionally it comes with questions