Chemistry Honors Lab: Titration

Lab: Titration

This lab's purpose was to practice our titration skills and calculation skills.  During the lab, my group and I titrated acetic acid and sodium hydroxide with 4 drops of phenolphthalein to visually signal when the equilibrium point just past.  Then we take notes on how much NaOH was used and how much acetic acid was used.  Using that and the given pH of vinegar (2.41) we were able to calculate the percentage ionization.  For this reaction, the percent ionization was 0.44% and the reason for this is that acetic acid is a relatively weak acid and sodium hydroxide only has one ionizable proton.  This percentage was calculated by dividing the molarity of H3O+ (.0039) by the molarity of acetic acid (.885) and then multiplying by 100.

Set Up

Titrated Solution

Chemistry Honors Lab: Chicago River Water Testing

Chicago River Water Testing

My group tested the nitrate levels of the Chicago River, about a one mile from Lake Michigan.  The test consisted of 50 mL of river water and two pre-made mixtures added to the sample.  These mixtures' purpose was to react with the nitrates and create a a pink color for the tester, in this case me.  The more intense this pink color, the more nitrates there were in the water.  If there are too many nitrates in the river, it may cause eutrophication.  High amounts of nitrates in drinking water could also lead to many problems in very young and unborn children, such as infant methemoglobinemia.  Two groups did this test, and the average "Q" value, or quality value, of the river was 100, meaning that water has perfect nitrate levels.  One way I or anyone could continue this great balance is to ensure that there car and its engine is working properly and that there is no chance of leakage of any fluid.

3 Things I Learned

1) Due to the near perfect balance that the bridge achieves, there are surprisingly small motors used to lift the Michigan Avenue bridge.

2) It took 12 years to build the Michigan Avenue bridge.

3) Chicago Sanitary District was established in 1887

2 Surprising Facts

1) The river flow was reversed to avoid polluting Chicago's main source of drinking water with its inhabitants' sewage.

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2) 2/3 of the men died when working on the canal in 1839-1839

1 Question

1) Whose idea was it to name 5 consecutive streets after the Great Lakes?

View from Michigan Ave. Bridge Mueseum

Color comparison to find nitrate levels

Chemistry Honors Lab: Calories in Food

Lab: Calories in Food

This lab was conducted to find calories in many nuts, ours being the brazil nut.  We did this by lighting a brazil nut on fire and heating a beaker with 50 mL of water and measuring the before and after temperatures.  

Questions

1) Did you measure a temperature change in the food sample or the water?

The water

2) Did you measure the energy released by the food sample or the energy gained by the water?

The food sample (brazil nut)

3) What happens to the small amount of energy that is not absorbed by the water?

That energy was absorbed by the the tin can propping the beaker above the flame.

4) Were you surprised by any of the results?  Explain

I was pretty surprised by how much energy was packed into that singal nut.  I never really thought of Calories in that way, I just thought that I need about 2000 of them everyday.  But now I have an image I can look back on to reflect on what the Calorie is in actuality.  

Chemistry Honors Lab: Specific Heat of a Metal

Lab: Specific Heat of a Metal

This lab was set up to find the specific heat of a metal by measuring the rise of temperature in a water bath that surrounded a heated sample of an unknown metal.  After taking measurements, we found the specific heat via the collected data and compared it to the known specific heats of a couple metals.  Our calculated specific heat was 894 J/kg oC.  This was closest to aluminum's specific heat, which in 901 J/kg oC.  This identification makes sense due to the the shinny silverish color the sample had.

Metal heating in water bath

Measuring the water temp with the metal sample