pH calculation (1 Viewer)

untouchablecuz

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Calculate the pH of a solution of 0.75 g barium hydroxide dissolved in 2.0 L
water.

I think I got the answer, I just need reassurance :D
 

katie tully

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well moles would be easy to work out from 0.75 g of barium hydroxide/mw

but

u tell us what you got first....
 

katie tully

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nm, stalling, procrastinating ... all of those other words that describe the art of evading assignments

u?
 

katie tully

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tee hee

when the AU dollar was 90 us cents or whatever, i got 2 text books incl. postage thru amazon for less than the cost of one text with postage thru the coop

:wave:
 

untouchablecuz

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i got pH = 11.34

not 100% if it's correct cause there's a step i'm not sure of (but it fits with the substance, basic)

and btw, thanks for the help guys LOL

edit: i'm pretty sure i got it wrong
 

lolokay

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molar mass of Ba(OH)2 = 137.3 + 2(16.00 + 1.008)
= 171.3g

so there are 0.75/171.3 = 4.38 * 10-3 moles of Ba(OH)2 in the 2.0L
So [OH-] = 2*(4.38 * 10-3)/2.0 as there are 2 OH- for each Ba(OH)2
[OH-] = 4.38 * 10-3

using [OH-][H+] = 10-14 for water
[H+] = 10-14/ [OH-]
= 2.28 * 10-12

pH = -log[H+]
= 11.64
 

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