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? ^_^

You are quite right about the acid concentration thing. My teacher said that it would screw up the test if someone had deluded the acid. Most of the time, hydrocloric acid is the only one that they use for doing forensic tests such as these.

Currently I am in the 8th grade, but I think I might want to be a Forensic Scientist when I grow up. The camp that i keep talking about was my state's Govornor's School for Math and Science. It was held at our biggest college, and only 60 students from the state could go. I was a really great experience.

Posted by Hope on 2002-08-20 06:02:13