Determination of Ph of strong and weak acids

Determination of Ph

Strong acid: the acid which is completely dissociates into ions

Strong acids examples: HCl, H2SO4, HNO3

because of complete dissociation the concentration of [H+] equals the concentration of the acid it self  so to determine the ph it equals : Ph= -log[H+]

In Weak acids:

weak acids partially dissociate into ions then the concentration of H+ is not equal to concentration of acid it self ,but we have to determine it 

then the [H+]= √ka Ca

Ka is dissociation constant of acid and Ca is concentration of acid {this relation is derived by Ostwalds}

the Ph of weak acid is the same as strong one : Ph= -[H+]

  

Electrochemical series

Any oxidation reduction reaction 

follow the series

This series arrange the elements according to their oxidizing and reducing ability:

the lower elements can replace the higher one in the solution, for instance:

 As shown in the pic. the zinc when placed in copper sulfate it replaces the copper ions by reducing it  while zinc it self is oxidized   

but, if we put a copper piece in zinc solution no chemical reaction occurs this is due to the zinc has higher reducing agent than copper

as previous also if we immerse an iorn in zinc solution nothing will occur due to zinc is higher reducing agent than copper

approaches for losing weight

in the last article we showed why exercise is useless to weight lose, here we propose some of raising diet type, the keto diet:

- KETO DIET:
to understand keto diet we have to know some metabolic information.

the main source of energy in body is glucose which comes from carbohydrate. 

when we eat high amount of carbohydrate the pancreas produce insulin which is hormone that helps the body to use carbohydrate, regrettably it is also reduce and inhibit fat burning.
this is called the insulin trap.

the keto diet aims to overcome this trap by eating low carbohydrate diet and compensating it with high fat content.

in addition to avoiding insulin trap, fats has high ability to promote satiety and reduce appetite, hence reducing food intake.
it has some other advantage such reducing epilepsy, possible cure of diabetes type 2 and fights cancer due to cancer major dependence on glucose metabolism.

it is to be noted that keto diet may cause some side effects, doctors call it keto flu: you may experience uncomfortable side effects such hunger, headaches, nausea, fatigue, irritability and constipation.

so it is best if you keep counseling doctors while you apply it.

why exercise is not the best way to lose weight.

while government agencies as well as food companies continue to present exercise as the complete solution of obesity, there is sixty study supports that exercise is just useless when it come to losing weight.

to understand why is it wrong, one has to understand the major ways where the body spend energy, as illustrated in this image the are 3 main ways our body burn calories:

1- resting metabolism: that is how much energy your body burns for basic functioning ,just to keep you alive.

2- thermic effect of food: which is how much energy required to breakdown food.

3- physical activity: which is any movement you do, which only account for 10-30 % of your daily calories burn.

 so, you can say why do not increase physical activity ?!

that is the problem, while you can increase the burning by physical activity your body just compensate it with reducing the resting metabolism portion.

your body simply adapted to it with the same amount of calories burned.

in addition, exercise create problem of it’s own.
you can raise your activity but it will increase your appetite which in turn will lead you to double the amounts you eat.
it is called compensatory behaviors: while you can go for a run before breakfast it will lead you to double you food potions.
hence, you just burn the same amount of calories ,beside you are eating more which will cause opposite result.
but then how do we lose weight ? do you have to give up to obestiy?
NO, the most effective way to lose weight is by controlling food intake.
there are many approaches to this ,if you interested read the next article:
approaches for losing weight

Replacement Titration

It is type of titration used when back titration or direct titration are insufficient.

Easly It  depends on the ability of metal to bind to titrant (e.g: EDTA) more than another metal.

to be clear we will take an example:

principles: 

1. 1- Ca+2 has higher affinity to bind to EDTA more than Mg+2
2. Mg+2 has higher affinity to bind to EBT more than Ca+2
3. color of EBT when binds to metal is wine red and has blue color in free form

procedure:

1. buret : contain EDTA
2. Conical : contain the EBT-Mg+2 and Ca+2

here the analyte (substance wanted to be mesured) is Ca+2, EBT is the indicator and it binds the Mg+2 giving color (wine red). This because Mg+2 has higher affinity to bind to EBT than Ca+2.

Now lets start titration: 

• the amount of EDTA added to conical will bind to Ca+2 because its higher affinity to EDTA
• now after adding more EDTA all free Ca+2 will be bound to EDTA 
• at the end addition of more EDTA will relase the Mg+2 from EBT and bind to EDTA, so after that free EBT will be in the conical giving blue color which called endpoint of the reaction

so here in replacement titration we depends on affinity of the analyte to both titrant and indicator
for example if we used Murexide indicator the previous reaction can not be occured, because Ca+2 can bind to Murexide.

so in replacement titration the analyte has low ability to bind to the indicator or give no sharp endpoint. also you need to use metal has higher affinity to the indicator as shown up.

ATP, ADP and AMP

It is adnosine triphosphate as shown in the figure, this molecule contains 3 phosphate groups.

the bond between the first phosphate group which directly bind to the carbon 5 of the pentose sugar is weak bond, but the other 2 bonds between the other 2 phosphate groups are called strong bonds which upon their breakage the high energy produced.

so in biological reactions when body needs energy it breaks the thirds phosphate group releasing energy and yield ADP( Adenosine diphosphate) 

and in some reaction also the second phosphate group also broken and yields AMP( Adenosine monophosphate)  

Human Immunodeficiency virus (HIV)

It is virus that attack the lymphocytes (B-Cells and T-cells)  of immune system which are responsible for the adaptive immune system.

• Mechanism of spreading: It binds to the DNA of cells by that: It contains RNA and Enzyme called Reverse transcriptase that converts RNA to DNA then this DNA binds to the DNA of cells and replicated with cells and also it is transcripted and translated with body enzymes producing more and more viruses.

• the hardest thing is that no drugs can stop it because it is RNA meaning it is changed all time making drugs inefficient. also it evolves if the medium around it is changed giving new virus(suc as if you take a drug to stop it this drug affect your body changing the internal medium then this virus change from it self like the evolution principle of darwin). so it is the worst virus because: 

1.  no drugs are effective 
2.  High ability to change according to the medium
3.  It is RNA not DNA meaning increasing exchange in its structure
4. It damage the most important system in the body ( immune system) making body with no defenses increasing infection with different other diseases