Post by: ~Dazzling Star~ on October 05, 2010, 04:13:47 pm
math:
1.straight line graphs :
-finding the equation of a line
-the mid coordinats....
-etc.....
2.graphing functions?!!?!
i have no idea what to do here :o :( :-\
chemistry:
1.drawing do and cross formulas
2.titration??(and calculations involved in it)
3.acids and bases (tell me what i need to know)
4.oxides?
5.chemical calculations
i will really appreciate it if anyone follows up with me throughout these portions especially in chemistry !!!
plz plz plz help me
Post by: elemis on October 05, 2010, 04:17:55 pm
Where m = gradient c = y intercept (the y coordinate of the point where it intersects with the y axis).
The mid coordinate is given by this formula :
Post by: Deadly_king on October 05, 2010, 06:02:22 pm
i just joined a new school in my 2nd year of IGCSE and it turns out that they have finished man topics that i haven't in math and chemistry,and these are the topics:
math:
1.straight line graphs :
-finding the equation of a line
-the mid coordinats....
-etc.....
2.graphing functions?!!?!
i have no idea what to do here :o :( :-\
chemistry:
1.drawing do and cross formulas
2.titration??(and calculations involved in it)
3.acids and bases (tell me what i need to know)
4.oxides?
5.chemical calculations
i will really appreciate it if anyone follows up with me throughout these portions especially in chemistry !!!
plz plz plz help me
This might help for chemistry :
http://www.s-cool.co.uk/gcse/chemistry/acids-and-alkalis.html
Maths :
http://www.s-cool.co.uk/gcse/maths/graphs.html
However these are GCSE notes. So I would advice you to chose only what you need and neglect what is not required in your syllabus :)
Post by: Freaked12 on October 05, 2010, 06:15:22 pm
Just give us a few questions and you will get the idea when we solve them
Post by: ~Dazzling Star~ on October 05, 2010, 06:47:07 pm
The general equation of a line is y = mx +ccan i use any coordinates regarding x1 x y1 &y2??
Where m = gradient c = y intercept (the y coordinate of the point where it intersects with the y axis).
The mid coordinate is given by this formula :
This gives the x coordinate
This gives the y coordinate
and i donot understand what an intercept is could u explain again
Post by: ~Dazzling Star~ on October 05, 2010, 06:48:46 pm
Straight line graphs are the easiest part in IGCSE curricula and same is the case with acids and bases.ca u tell me the main things i should know abt in acids and bases??
Just give us a few questions and you will get the idea when we solve them
Post by: Twinkle Charms on October 05, 2010, 07:44:04 pm
Post by: elemis on October 06, 2010, 03:34:49 am
can i use any coordinates regarding x1 x y1 &y2??
and i donot understand what an intercept is could u explain again
If the two coordinates of a line are (1,2) and (6,5) then X1 = 1 X2 = 6 and Y1 = 2 and Y2=5.
You see the red line how it crosses the y axis ? The coordinates at which it crosses is given to be (0,7)
Therefore the y-intercept is 7.
Post by: Deadly_king on October 06, 2010, 06:00:39 am
ca u tell me the main things i should know abt in acids and bases??ACIDS :
1. An acid is a substance that will produce hydrogen ions (H+) on dissolving in water.
There are two types of acids :
(i) Strong acid ---> Complete ionisation
(ii) Weak acid ---> Partial ionisation
Examples of strong acids are HCl and H2SO4 while all organic acids are weak acids.
Properties of acids :
1. An acid has a sour taste.
2. An acid will turn moist blue litmus paper red.
3. An acid will react with reactive metals to liberate hydrogen gas.
4. An acid will react with carbonates to liberate carbonates.
Tests for acids.
1. When moist blue litmus paper is brought into contact with an acid, there is a colour change from blue to red.
2.When solid sodium carbonate is brought into contact with the acid, there is effervescence and a gas carbon dioxide which turns lime water milky is liberated.
BASES :
1. An alkali or base is a substance that will produce hydroxide ions (OH-) on dissolving in water.
Properties of alkalis :
1. An alkali has a soapy feel.
2. An alkali will turn moist red litmus paper blue.
3. An alkali will react with an acid to form a salt and water.
4. An alkali when heated with an ammonium salt will liberate ammonia gas.
Test for alkali :
1. When moist red litmus paper is placed into a alkali, there is a colour change from red to blue.
2. When an alkali is heated with ammonium chloride, a gas ammonia that turns red litmus paper blue is liberated.
Post by: Deadly_king on October 06, 2010, 07:03:32 am
1. A basic oxide is a metallic oxide that will react with an acid to form salt and water only.(Example :MgO)
Equation : MgO + 2HCl ----> MgCl2 + H2O
2. An acidic oxide is a non-metallic oxide that will combine with water to form an acid.(Example : SO3)
Equatio : SO3 + H2O ---> H2SO4
3. An amphoteric oxide is a metallic oxide that has both basic and acidic properties, that is it can behave as an acid as well as a base.(Example : PbO)
Equation : (i) PbO + 2HCl ----> PbCl2 + H2O
(ii) PbO + Ca(OH)2 + H2O ----> Ca[Pb(OH)4]2
4. A neutral oxide is a non-metallic oxide that has neither basic nor acidic properties.(Example : CO2)
I guess that's all you need to know concerning oxides. :)
Post by: ~Dazzling Star~ on October 06, 2010, 04:34:54 pm
Oxides : There are four types of oxides.
1. A basic oxide is a metallic oxide that will react with an acid to form salt and water only.(Example :MgO)
Equation : MgO + 2HCl ----> MgCl2 + H2O
2. An acidic oxide is a non-metallic oxide that will combine with water to form an acid.(Example : SO3)
Equatio : SO3 + H2O ---> H2SO4
3. An amphoteric oxide is a metallic oxide that has both basic and acidic properties, that is it can behave as an acid as well as a base.(Example : PbO)
Equation : (i) PbO + 2HCl ----> PbCl2 + H2O
(ii) PbO + Ca(OH)2 + H2O ----> Ca[Pb(OH)4]2
4. A neutral oxide is a non-metallic oxide that has neither basic nor acidic properties.(Example : CO2)
I guess that's all you need to know concerning oxides. :)
thx soo much....can u tell me abt titration??
Post by: ~Dazzling Star~ on October 06, 2010, 04:37:30 pm
If the two coordinates of a line are (1,2) and (6,5) then X1 = 1 X2 = 6 and Y1 = 2 and Y2=5.ok i get it now thx.... could you tell me abt graphing function?
You see the red line how it crosses the y axis ? The coordinates at which it crosses is given to be (0,7)
Therefore the y-intercept is 7.
Post by: elemis on October 06, 2010, 04:38:08 pm
thx soo much....can u tell me abt titration??
Basic titration involves neutralization of an acid with an alkali.
The idea behind the experiment is to determine the concentration of the either the acid or alkali.
I'm sure your textbook has something more on it and you could check youtube for some example titrations being carried out,
Post by: elemis on October 06, 2010, 04:39:26 pm
ok i get it now thx.... could you tell me abt graphing function?
Welcome.
Umm, could you specify what you dont understand ? Like give me an example question.
Post by: ~Dazzling Star~ on October 06, 2010, 04:52:45 pm
Welcome.
Umm, could you specify what you dont understand ? Like give me an example question.
ok, i really have no idea can u give me an example past paper question??
thx again
Post by: elemis on October 06, 2010, 04:58:36 pm
ok, i really have no idea can u give me an example past paper question??
thx again
The best thing for you to do would be to read your textbook and attack some of the questions. If you have any problems regarding a certain topic then post here and we'll help you out ;)
Post by: ~Dazzling Star~ on October 06, 2010, 05:01:58 pm
The best thing for you to do would be to read your textbook and attack some of the questions. If you have any problems regarding a certain topic then post here and we'll help you out ;)ok soon hopefully.........:)
Post by: Deadly_king on October 06, 2010, 05:37:13 pm
Yupz.......Ari just showed you the right track ;)
Now carry on with some past papers after consulting your textbooks. Then if you have any problem, we'll be glad to help :)