albertlee

please help according to my previous message... thx

so, Borek, how did you calculate that????? oh come on, plz help...

-log(concentration of H+ ions) the above is the formula for calculating the ph of an acid... however, when the concentraion is 1M, the pH is 10.. but how could that be?? it should be less than 7, because it is an acid.. secondly, how do you calculate the "alkalidity" of pH?? thx

How do electrons reduce the dissolved O2 gas? since O2 gas is covalently bonded.... when you say REDUCE, do you mean you gain O2 gases by gaining its electrons?? a bit confused here.... plz help

let me rephrase...

extending from Atheist, a2b + b2c + c2a > (a+b+c)(abc) ==> a2b + b2c + c2a > a2bc+ab2c+abc2 therefore: 0 > (c-1)a2b+(a-1)b2c+(b-1)ac2

below is what I discovered.. If you heat up the water up to 100c, ie, it is boiling, the temperature no longer rises further... I know the reason can be explained on the kinetic and potential energy of water molecules, but I just dont know how... any body?? thx

any one????

so, how does the hydrated iron oxide come from?? ps, sorry, I cant understand Lucid's steps of chemical equations....

plz, where is jDurg?? plz help me!!

for what to occur???

At my current level of chemistry learning at school, explanation of the chemical cells is at the level of "how", but I want to know "why" for the 1st instance, how come the electrons move through the metals at the negative pole along with wires instead of moving towards the electrolyte?? 2ndly, what makes the less reactive repulsive from reacting with the electrolyte if the more reactive metal pole is in presence??? thanks

I know that when iron crodes, it also means it rusts... however, I thought, as redundant time has gone by, iron will react will oxygen apparantly, but in my textbook, it says it only rusts with oxygen+water...why????

thanks swansont, but a question on your wording.. what does T' mean? btw, why put a hypostrophe??

yes, but can you explain this with the potential and kinetic energy that Jdurg has demonstrated?? thanx

the really tricky thing here is, how do you define the sum of energy?? since of course, water also has energy even when it's at 0c.... probably you people have to show me with equations to demonstrate your view..

If an amount of water is added to another amount of water which is 3 times more in volume with temperature 10, what is the temperature of the water, which when added to another, the overall temperature is 20?? specific heat capacity for water = 4200J/kg c below is my solution Let's assume the amount of water is 1 and 3. Say, the energy used to heat up the amount of water of 3 to 10c from 0c is: 3*4200*10 = 42000*3J the energy used to heat up the total amount of water from 0c to 20c is: 4*4200*20 = 84000*4J = 42000*8J Ok, subtract the nergy used to heat up the total amount by the energy used to heat up only the amount of water of 3, and the answer is: 5*42000J and that's the energy used to heat up the water of 1... so, 4200*1*t = 5*42000J t = 50c = temperatue rises from 0 using the according amount of energy... so, what I am asking is, can you people find a simpler method apart from the above?? thx

and one more supplement question to the previous, why the greater difference in reactivity of two different metal electrodes cause a greater voltage?

and yet, another question. Say, a chemical cell with Copper and magnesium electrodes and HCl electrolyte.. I know Magnesium is more ready to give up its electrons, that's why it reduces in size... however, what tells Copper not to give up its electrons?? I was like expecting both give up their electrons although Magnesium has a faster rate.....

thanks jdurg.... now I have come a few more questions.... What keeps the eletrons from "falling" towards the necleus? In addition to your post, what is happening in ionic bonding instead? Take for example, the difference between Potassium reacting with water to form Potassium Hydroixde and Cesium to form Cesium Hydroxide.... thanx

any body????? btw, can any one explain the graph of post #15??? I just cant imagine how can potential energy be negative....

thanks... however, I have only met the idea of "energy" in atoms now... so I may not be all clear.. so, jdurg.. in your post, do you mean that if electrons are nearer to the nucleus, potential energy decreases and kinentic energy increases, if are furthur apart from.. vice versa?? secondly, your exp with building is abit obscure to me.... does that refer to the energy level, or the distance from the nucleus?? As a consequence, I have some trouble picturing why bonds formed release energy ... plz help.. thx

strange.... this is my second year at school studying chemistry... why do I never encounter "electronstatics" at school? by the way, for the "potential energy", I think some of you have answered this long ago, but I wasn't able to absorb it.... if you people are kind enough... can you tell me about that again? (I only know "potential energy" as energy obtained due to the object's position, in most cases, due to gravity. However, I cant picture any possible potential energy in particles...) thx

well, at that particular time, I wasn't able to understand what you were saying...therefore I bypassed it, because I already got my answer from that thread......sorry..