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### Topic: Acid and Base Word Problem  (Read 9708 times)

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#### Kabuze

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##### Acid and Base Word Problem
« on: April 06, 2011, 08:51:32 PM »
A nitric acid solution is found to have a pH of 2.70. Determine each of the following:
a. [H3O] <-2.0 x 10^-3 M (antilog(-pH))

b.[OH] <-5.0 x 10^-12 M (1.0 x 10^-14/2.0 x 10^-3)

c. The number of moles of HNO3 required to prepare 5.50L of this solution.
moles=concentration x volume right? So (2.0 x 10^-3 M) x 5.50 L = 1.1 x 10^-2 moles

d. The mass of the moles of HNO3 in the solution in part c.
1 mole of HNO3=63.01g/mole
1.1 x 10^-2 moles x 63.01 g/mole = 6.93 x 10^-1 grams right?

e.The milliliters of concentrated acid needed to prepare the solution in part c. (Concentrated nitric acid is 69.5% HNO3 by mass and has a density of 1.42 g/mL.)
I have literally no idea of how to do this one, any tips would be helpful and appreciated. (:

#### Borek

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##### Re: Acid and Base Word Problem
« Reply #1 on: April 07, 2011, 04:29:05 AM »
e.The milliliters of concentrated acid needed to prepare the solution in part c. (Concentrated nitric acid is 69.5% HNO3 by mass and has a density of 1.42 g/mL.)
I have literally no idea of how to do this one, any tips would be helpful and appreciated. (:

You already know the mass of acid - calculate mass of the solution (you will need to use definition of %w/w), then convert to volume (using definition of density).
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