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# Explain how some solutions can have a negative pH? watch

1. It's only a 1 mark question i don't know the answer to. Can somebody pls tell what it is? Thanks in advance.

x Heidi
2. Ok the formula for pH is - log [H+]

Now i don't know if you take maths and have studied logs properly but if the pH is 5 then that means that 10 to the MINUS 5 = the concentration of hydrogen ions

That would mean that if the pH is 2 then one over 10 squared (1/100) is the concentration of hydrogen ions

Now if there is a really massive concentration of hydrogen ions then the concentration is going to be greater than 1 mol / dm3

i.e. greater than 10 to the 0

As soon as the concentration of hydrogen ions gets bigger than 1 mole, then the power of 10 gets bigger than 0

That means that when you make it negative.... it's actually a negative number
3. Maths is so very bloomin useful if you take a science. Makes every single calculation so ridiculously easy (rates of reaction, titrations, concentrations, waves, molar equations & gas volumes, solubility constants, partial pressures - the list is huge of the topics that most maths students find very very easy. huge advantage eh?)...sorry, got carried away...
4. to put it simply, when [H+] > 1 PH will be negative.
5. (Original post by CrazyChemist)
Maths is so very bloomin useful if you take a science. Makes every single calculation so ridiculously easy (rates of reaction, titrations, concentrations, waves, molar equations & gas volumes, solubility constants, partial pressures - the list is huge of the topics that most maths students find very very easy. huge advantage eh?)...sorry, got carried away...
thanks for sharing that

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