Chemistry

Exercise 2: Gas and Reactions

Data Table 2. Carbon Dioxide Reaction Observations. Please be specific and detailed

Reaction

Observations

Ca(OH)2 + CO2

Gas bubbles appeared almost immediately. Solution became opaque white in color.

CO2 + BTB

Bubbles formed and solution changes color from blue to yellow/copper

CO2 + Flame

The flame went out almost immediately.

Ca(OH)2 + Antacid/water gas

Antacid/water gas + Smoldering toothpick

Ca(OH)2 + Breath

Solution turns lightly opaque and milky in appearance

Questions

A. Write a balanced chemical equation (with phases) for the reaction of carbon dioxide and limewater (Ca(OH)2). What are the physical descriptions of the products that are formed (i.e., what do they look like)?

B. When the bromothymol blue (BTB) was exposed to the CO2 gas, what color was the solution? Did the color indicate presence of an acid or base? Explain how you know this.

C. Did the reaction between the antacid tablet and the tap water produce hydrogen, oxygen, or carbon dioxide gas? Using your results from Exercise 1 and Exercise 2, explain how you came to deduce the identity of the gas that was formed. Be specific.

D. Based on your observation of the reaction that occurred when limewater was exposed to your breath, what gas did you exhale? Using your observations from Data Table 2, explain how you came to deduce the identity of the gas. Be specific.

E. What is another simple way to generate carbon dioxide gas?

F. Carbon dioxide is used in certain types of fire extinguishers. Based on what you learned in thi lab, what would happen if the extinguisher was filled with oxygen gas? What about hydrogen gas?