Calculate the hydronium ion and hydroxide ion concentrations in human blood at 25oc

Using the equation, pH = − log [H+] , we can solve for [H+] as,

− pH = log [H+] ,

[H+] = 10−pH.

Exponentiate both sides with base 10 to "undo" the common logarithm. The hydrogen ion concentration of blood with pH 7.4 is,

[H+] = 10−7.4 ≈ 0.0000040 = 4.0 × 10−8 M.

b. is the answer hoped i        

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol