Sig Figs in 6B3

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Sig Figs in 6B3

Postby AnnikaMittelhauser4E » Fri Dec 06, 2019 2:03 am

6B3 says "A careless laboratory technician wants to prepare 200.0 mL of a 0.025 M HCl(aq) solution but uses a volumetric flask of volume 250.0 mL by mistake. (a) What would the pH of the desired solution have been? (b) What will be the actual pH of the solution as prepared?"

The textbook says the answer for A is 1.6, but shouldn't 1.60 be the correct amount of significant figures? It is just -log(0.025), and 0.025 has two significant figures, which I thought meant the answer needed two digits to the right of the decimal point.

I ran into the same confusion with part B as well. Answer listed as 1.7 when I thought it should be 1.70

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Re: Sig Figs in 6B3

Postby WesleyWu_1C » Fri Dec 06, 2019 3:50 am

Yeah, I also believe the answers should be 1.60 and 1.70.

Maya Pakulski 1D
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Re: Sig Figs in 6B3

Postby Maya Pakulski 1D » Fri Dec 06, 2019 10:04 am

When looking at pH and pOH there are different significant figure rules, here's a website that explains what they are.

Siya Shah 1J
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Re: Sig Figs in 6B3

Postby Siya Shah 1J » Fri Dec 06, 2019 10:20 am

Likely the two sig figs comes from the value of concentration 0.025 M.

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