Assumed Knowledge Assignment help! (1 Viewer)

[Jono_2007]

I dont know how i should aproch these questions below:
5)
b.Compare the similarities and differences between different elements in a group in the periodic table.
c.Compare the similarities and differences between different elements in a period in the periodic table.
d. Describe where elements that are classified as metals are located on the periodic table.

thanks in advance!

 

[insert-username]

I dont know how i should aproch these questions below:
5)
b.Compare the similarities and differences between different elements in a group in the periodic table.

Firstly, if you don't know much about the Table, check out Wikipedia's page on it - it's a good intro. Use Google to find out more info (search for "periodic table groups", etc.)

Groups on the Periodic table run downwards. There are 8 groups, and all of the elements in each group (the halogens, the noble gases, etc) have the same properties, i.e. everything in the Noble Gas group is a gas and unreactive. Differences are that as you go further down the table, the elements get heavier and larger, as well as possessing a higher "electronegativity" (the ability to attract electrons to itself).

c.Compare the similarities and differences between different elements in a period in the periodic table.

Periods run across the periodic table. Elements close to each other in the same row have a similar molecular weight, but usually different properties.

d. Describe where elements that are classified as metals are located on the periodic table.

All metals are located on the left hand side of the periodic table. Most of the elements are actually metals - only the elements to the far right are non-metals or semi-metals. In Wikipedia's periodic table, the metals are everything up to the zig-zag line of "Metalloids".

I hope that gets you started. The periodic table isn't the easiest subject to delve into.


I_F

 

[Jono_2007]

thanks heaps, but i have noticed that your answer is always wikipedia, but then again not really lol...thanks again

Even though you answered the question for me. what i was asking was how do i pesent the information not where can a get the information from or what are groups and/or periods. i.e/ for question b), did it want an example.

Thats all! Thanks

 

[insert-username]

thanks heaps, but i have noticed that your answer is always wikipedia, but then again not really lol...thanks again

Even though you answered the question for me. what i was asking was how do i pesent the information not where can a get the information from or what are groups and/or periods. i.e/ for question b), did it want an example.

Thats all! Thanks

Hehe, for most topics, Wikipedia's an excellent basis for your research.

Sorry I didn't cover the real question. For these types of questions, you should write a paragraph answer with examples (examples are always good as they show you can back up your comments with knowledge). My start for question 5b would be something like:

Different elements in the same group of the Periodic Table have many similarities. They tend to exibit similar physical properties; for example, the noble gases argon and krypton are both chemically inert and practically unreactive with any substance.... However, elements in the same group in the Periodic Table also have some differences. Elements lower down in a group have a larger atomic radius due to the increased number of particles in the nucleus

And so on. When you're asked to make a comparison, make sure you make the comparion. Happy working!


I_F

 

[Riviet]

I dont know how i should aproch these questions below:
5)
b.Compare the similarities and differences between different elements in a group in the periodic table.
c.Compare the similarities and differences between different elements in a period in the periodic table.
d. Describe where elements that are classified as metals are located on the periodic table.

thanks in advance!

For b, you could explain the similarities and differences of the elements in each group. Do a paragraph for each group.

For c, you could write a paragraph for each period, I would suggest doing a minimum of the first two periods because these two are most important and you can explain the 3rd and 4th if you think it is necessary.

For d, a paragraph or two is sufficient, you should talk about things such as metals being reducing agents (sorry if this confuses you ) or undergo oxidising themselves, hence they have fewer electrons in the outter shell, and therefore they are mainly in groups 1, 2, 3.

 

[Jono_2007]

Thanks riv!
Another question:
In the following hypothetical chemical reaction, 4.0g of Q react with 10.0g of R. This produces 6.0g of substance S.
2Q+R-->S+3T
a)What mass of substance T would form during this reaction. Justify your answer.

b) Compare the number of atoms that were present before the reaction, with the number of atoms that were present after the reaction. Justify your answer.


My answer for a) was 8.0g, because 14-6=8. dont know if thats right! Cant justify it.

Thanks

 

[insert-username]

Another question:
In the following hypothetical chemical reaction, 4.0g of Q react with 10.0g of R. This produces 6.0g of substance S.
2Q+R-->S+3T
a)What mass of substance T would form during this reaction. Justify your answer.

My answer for a) was 8.0g, because 14-6=8. dont know if thats right! Cant justify it.

8.0g is correct. The mass of the products in any chemical reaction is equal to the mass of the reactants, so the mass of 2Q + R must equal the mass of S+3T.

[b) Compare the number of atoms that were present before the reaction, with the number of atoms that were present after the reaction. Justify your answer.

There are still exactly the same number of atoms present before and after the reaction. The mass of the products in any chemical reaction must be equal to the mass of the reactants, thus the number of atoms does not change (even if some new substance was created). The Particle Theory of Matter, remember?


I_F

 

[Jono_2007]

Yes thats what i was thinking of putting more or less, i started saying like the LHS needs to = the RHS or something.

Thanks, heaps...To my buddy list..add insert_username.. there we are! Cheers

 

[Riviet]

Ah I get it too now. Nice work guys.

 

[insert-username]

Thanks, heaps...To my buddy list..add insert_username.. there we are! Cheers

Just for that, I'll add you too. Just remember that chemists aren't mathematicians, so more often than not you'll need to write out a sentence reason rather than a mathematical one.

It sounds like you're well-set for a good year of Chemistry. Best of luck for Year 11.


I_F

 

[Jono_2007]

I have another question, and it seems that you only have answers so yeah..!

a)Provide the name and chemical formula of a solid, liquid, and gasious fossil fuel.

I dont know any solid fossil fuel other than coal, but it has no definite formula.
Alkanes are all hydrocarbons, and gases, so i'm set for these. Liquid? dontknow either!

Thanks! :d

 

[insert-username]

I dont know any solid fossil fuel other than coal, but it has no definite formula.
Alkanes are all hydrocarbons, and gases, so i'm set for these. Liquid? dontknow either!

Not all hydrocarbons are gases. Petrol is a mixture of alkanes (mainly octane), so there's your liquid fossil fuel.

As for solid fossil fuel, pure coal is about 95% carbon, with a few impurities like sulfur. However, I'm pretty sure good old C will do for coal.


I_F

 

[Jono_2007]

fossil fuel | Chemical formula
Coal_(s) ----> C
Octane_(l) -----> C₈H₁₈
Methane_(g) -----> CH₄

So thats it oK. done thanks alot! I'm begining to rely on you. and you regulary help people out, you should apply for benefactor.

 

[vizman]

8.0g is correct. The mass of the products in any chemical reaction is equal to the mass of the reactants, so the mass of 2Q + R must equal the mass of S+3T.
There are still exactly the same number of atoms present before and after the reaction. The mass of the products in any chemical reaction must be equal to the mass of the reactants, thus the number of atoms does not change (even if some new substance was created). The Particle Theory of Matter, remember? [/I][/I]
I_F

isn't it the Law of the Conservation of Mass ?

 

[Riviet]

isn't it the Law of the Conservation of Mass ?

That's correct vizman, the Law of the Conservation of Mass is what insert-username stated previously. I "think" the The Particle Theory of Matter is the theoretical version of the law.

 

[insert-username]

isn't it the Law of the Conservation of Mass ?

The Law of Conservation of Mass is also correct, but the Particle Theory states that matter can be neither created nor destroyed - only changed into different forms - that was the point I was getting at, sorry.


I_F

 

[Jono_2007]

How long should i make my anwer to this question, and what structure.
Discuss some reasons for concern about mankinds continued use of fossil fuels.

 

[pLuvia]

With discuss questions you need to address the advantage and disadvantages, I'm sure dot point format under each subtopic is fine.

 

[Riviet]

How long should i make my anwer to this question, and what structure.
Discuss some reasons for concern about mankinds continued use of fossil fuels.

The question is asking only for reasons of concern, which implies you only need to discuss the disadvantages of mankinds continued use of fossil fuels. Just use your basic paragraphing structure to answer this.