How would you find the pH of a solution with a [H+] of 4.56 x 10^-5

Question

justin_lee · Answer

pH is found by taking the log10 of the inverse amount of hydrogen ions:
$$pH = \log_{10} (\frac{ 1 }{ [H ^{+}] }) = -\log_{10}([H ^{+}]) $$
Just plug in the concentration of hydrogen into the -log operator. Let me know what you get for pH so that I can confirm.

pounce0129 · Answer

@Justin_Lee i got 4.34

justin_lee · Answer

I got that too.

pounce0129 · Answer

you are a life saver, thank you soooo much :)

pounce0129 · Answer

@Justin_Lee  can you help me with one more?

justin_lee · Answer

Sure.

pounce0129 · Answer

find the pH of a 2.3 L solution containing 4.5 grams of HNO3

justin_lee · Answer

Your first step is to convert the grams value to concentration. Do you know how to do that?

pounce0129 · Answer

so like grams per liter?

justin_lee · Answer

What were the units of the 4.56 x 10^-5 that you posted before? grams/L or M?

pounce0129 · Answer

it just says [H+]

justin_lee · Answer

Hydrogen and hydronium ions are usually represented as concentrations of M (mols/L). Do you know how to convert from grams to mols?

pounce0129 · Answer

yes, so i would be 4.5/63.012

pounce0129 · Answer

*it

pounce0129 · Answer

and you would get 0.0714 moles

justin_lee · Answer

Yup. Now convert from mols to concentration.

pounce0129 · Answer

@Justin_Lee i got 1.51, is that right?