You have a little beaker with an unknown amount of acid indicator solution in it. Over this beaker, you have a tube marked in ml. increments. This tube is marked backwards, it starts at 0 at the top and goes to 25 at the bottom. This tube contains 25ml. of hydrocloric acid (.01 concentration), which will drip out one drop at a time into the beaker. The acid indicator will eventually turn magenta and you will then close off the tube.
On one such test you recorded that you started out with 10.2ml in the tube. You used it down to the 24.8ml area. At which time you refilled the tube to 12.1ml. You shut off the tube at 13.1ml, when the acid indicator was a nice shade of magenta.
Now, please give me the equation for how much acid indicator was in the beaker in mols, and use it to actually find how much was in it, also in mols. For bonus points, tell me how this equation would be helpful in certain forensic investigations.
You wouldn't think a 13 yr. old would want to put you through such a hard time of it, would you? ^_^
(In reply to
Acid Concentration by Hope)
To be more specific, to solve the problem, you need to know how many moles of HCl are in every milliliter of acid. If you are a crazy psycho scientist and are using pure HCl, then your data won't be very accurate, and it's a little suicidal to try to pour it into a skinny tube. You also haven't provided the density of pure HCl which is a bit of a pain to look up for most people.
Generally in lab situations like this, you have a solution of acid in water with a known molarity. Then it's easy to know the number of moles per liter.
Which situation did you have in mind?
re: Acid Concentration
