Chemistry Lab 3 Properties of Gases

 Questions

A. Give two reasons why we fill the gas generator test tubes almost to the top with chemicals? The first reason is that we want to obtain pure gas and by minimizing the amount of air in the top this will maximize the gases purity. Also, some gases may react differently to air. Minimizing contact with air assures a better outcome.

B. What happens to the zinc in the hydrogen generation experiment? It dissolved and formed hydrogen and zinc chloride.
C. What happens to the manganese in the oxygen generation experiment? The manganese seemed like a catalyst because it sped up the rate of the chemical reaction.
D. Write a balanced equation for the reaction between O2 and H2. 2H2 + O2 ==> 2H2O
E. What is the function/purpose of the bromothymol blue in the CO2 experiment? The Bromothymol blue changed color from blue to green and then it turned yellow. After the CO2 was mixed with water, I think carbonic acid was formed. This can measure the amount of CO2 present, a lot of CO2 will show yellow and very little or no CO2, the bromothymol will remain blue.
F. Bromothymol blue is blue in the presence of basic solutions, and yellow in the presence of acidic solutions.

If your solution is a murky green, what might you assume about the solution? I would assume that the solution is neutral if it is a murky green. With the acidic solution, the blue turns yellow.
Flow Chart

Fill four test tubes with distilled water.
Add 2-3 drops of bromthymol blue to each test. Part 1: Oxygen
Add a small amount of manganese dioxide in an empty test tube. Then add a small amount of Hydrogen Peroxide.
Immediately stopper the test tube.
Take the stopper out.
Repeat these steps for Part 2: Hydrogen and Part 3: Carbon.
Record data and answer questions.