PH help (1 Viewer)

[obelisk]

ok soo this is the question i need help on "find the concentration in mol/L when given the ph"

A. 3.26
B. 8.32
C. 5.00

if u can plz show me the basic how to do it on a calculator it would be great

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[minijumbuk]

Concentration of what? Assuming it's the concentration of H ([H⁺] )only, and not any polyprotic (More than 1 H+), then:

pH = - log₁₀ [H⁺]
[H⁺] = 10^-pH

A: [H⁺]= 10^-3.26
Press that on your calculator
B/C: Do the same thing, but with different values (8.32 and 5)

 

[brenton1987]

For B you need to use the pOH because of the self ionisation of water.

pOH = 5.68
10^{-5.68[/sub]
2.08929*10-6 mol.L-1 OH-}

 

[minijumbuk]

It didn't tell you whether to find [OH^-] or [H⁺] though =O

 

[Martyno1]

pOH isn't in the HSC Chem syllabus.