Biology; Chemistry; Physics: Post your doubts here!

[sweetiepie]

AC and DC is that AC is an alternating current (the amount of electrons) that flows in both directions and DC is direct current that flows in only one direction; the product that is flowing being electrons. AC power is what fuels our homes. The wires outside of our house are connected at two ends to AC generators. DC is found in batteries and solar cells. Both AC and DC employ magnets to repel electrons. Electrons are negatively charged particles that are one of 3 components that make up an atom. Negative charges will repel negative charges and positive charges will repel positive charges, so one only needs to introduce a negatively charged item next to electrons to force them to move in the opposite direction. Likewise, you can attract electrons by introducing something that is positively charged into their environment drawing the electrons to it. This property of electrons is what allows for AC power to work; that is, they switch directions constantly. The picture to the left is a demonstration of AC power at work. The constant switching of directions is evident in the dotted appearance of the light lines.

HOPE IT HELPS

 

[SalmanPakRocks]

can anyone explain me the difference between a.c and d.c currents?

A.C Currents:
These are called Alternating Currents and are produced by inducing E.M.F in the soleinod. The main electricity works on A.C currents as these are high voltage currents. These Current form Oscillatory movements when plotted in the graph.

D.C:
These are the direct current which are produced by chemical reactions inside a Cell or a battery. The voltages of these currents are low and are mainly used in simple circuits. The Movement of this current when plotted in the graph forms a straigh line.

Hope this clears out. This is a simple defination which is easy to remember.

 

[GetSomeLife]

Hey...pl help me wid my questions..
They are the only ones troubling me!!

 

[SalmanPakRocks]

where r ur questions?

 

[SalmanPakRocks]

When water reacts with acid HCl, it forms H3O and Chlorine
But wat happens wen it reacts wid Sulphuric acid

When Water reacts with H2SO4 I think the sulphuric acid get diluted, cuz it should make H2SO4 + H2O. Anyways I ain't conformed about this, neither did i ever encounter question related to it. Can u tell me any question which specify this?

Anothr 1 i m lookin fr is:
An acid has the formula of HY or H3Y. How can we know which one is correct by using aqueous solutions of the acid and Sodium Hydroxide. Assume that the concentration of both of them is the same(0.1 mol/dm cube)???

:%) :%)

where is this question from. And which Acid? :%)

 

[Anon]

Electrons are negatively charged particles that are one of 3 components that make up an atom.
HOPE IT HELPS

Just wanna clarify, that actually Atom is made of many sub atomic particles..
We have only three in our syllabus. (Protron, Neutrons and electrons ) but there are in actual many...

 

[SalmanPakRocks]

^^ I think its a defination copied from some other website so contains info NOT included in our syllabus.

 

[Anon]

When water reacts with acid HCl, it forms H3O and Chlorine
But wat happens wen it reacts wid Sulphuric acid

When Water reacts with H2SO4 I think the sulphuric acid get diluted, cuz it should make H2SO4 + H2O. Anyways I ain't conformed about this, neither did i ever encounter question related to it. Can u tell me any question which specify this?

Anothr 1 i m lookin fr is:
An acid has the formula of HY or H3Y. How can we know which one is correct by using aqueous solutions of the acid and Sodium Hydroxide. Assume that the concentration of both of them is the same(0.1 mol/dm cube)???

:%) :%)

where is this question from. And which Acid? :%)

About the latter, I think,
We mix the acid and sodium Hydroxide

if it is H3Y: solution will be acidic
HY: Solution will be neutral

 

[SalmanPakRocks]

hmmm what do u mean by mixing Acid and NAOH ??
I mean acid + Base will result in Salt + water i.e neutrilization.

 

[Anon]

It was a guess.

Logic is: for neutralisation, there should be equal moles of acid and base..

in H3Y, Hydrogen given off is 3 per mole.
in HY, it is 1.

in NaOH, there is only one hydrigen per single mole

so solution will be acidic in H3Y, and neutral in HY..

I repeat... its a mere guess..

 

[SalmanPakRocks]

hmmm but its a strange question, don't u think?
I mean there is a whole senario given to us in the ATP.

 

[Anon]

yeah, strange and scary..

BTW, you know about Dative covalent bond?

 

[SalmanPakRocks]

0.o what?
is that in they syllabus??

 

[Anon]

It isnt..

but it came in nov 10... I believe

 

[SalmanPakRocks]

What? Are u sure?
I mean how can something which isn't in the syllabus come in the paper? :Search:

 

[Anon]

It isnt the first time... they stretch the syllabus a bit

Attempt this question: (from Nov 10)

(ii) Carbon monoxide has a triple covalent bond.
Draw the electronic structure of carbon monoxide. Show only the outer electrons.

 

[Gémeaux]

It isnt the first time... they stretch the syllabus a bit

Attempt this question: (from Nov 10)

(ii) Carbon monoxide has a triple covalent bond.
Draw the electronic structure of carbon monoxide. Show only the outer electrons.

for this question they give u marks even if u dnt show the dative bond. just drawing 3 pairs of covalently bonded electrons wud do, though its better to have a concept of wat dative bonding is. another question fr ammonium ion ws also there, even in dat they didnt deduct marks fr not showing dative bond.

 

[GetSomeLife]

hmmm what do u mean by mixing Acid and NAOH ??
I mean acid + Base will result in Salt + water i.e neutrilization.

Its got nothin to do wid the products....the question just asks how do we confirm the formula

 

[multixamza01]

A coordinate covalent (dative) bond is a special bond because it involves a shared pair of electrons that came from a single atom. Check the notes i provided on my thread ''Chemistry Notes Available''. It's all there in detail.

And yeah it is in the syll.

 

[Anon]

A coordinate covalent (dative) bond is a special bond because it involves a shared pair of electrons that came from a single atom. Check the notes i provided on my thread ''Chemistry Notes Available''. It's all there in detail.

And yeah it is in the syll.

it isnt