Identification of Gases

Identification of Gases

Identification of Gases
Hands-On Labs, Inc.
Version 42-0189-00-02 Lab Report Assistant

This document is not meant to be a substitute for a formal laboratory report. The Lab Report
Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data
tables that should be addressed in a formal lab report. The intent is to facilitate students’
writing of lab reports by providing this information in an editable file which can be sent to an
instructor. 

Exercise 1: Gas and Flame Tests
Data Table 1. Gas Observations.
Chemicals
HCl + Zinc
Hydrogen Gas + Flame
Mn + H2O2
Oxygen Gas + Smoldering toothpick
Gas Mixture + Flame Observations
The contents fizzed and bubbled
Hydrogen gases formed and popped when added to flame.
Heating of molecules caused bubbles in solution
A rapid relighting of the flame
The flame was presenting a popping with a light flash Questions

A. Write a balanced chemical equation describing the reaction of zinc and hydrochloric acid.
Zn+ 2HClZnCl2 + H2 (gas) 

B. What gas was produced by the reaction of zinc and hydrochloric acid? How did this gas
behave in the presence of fire?

Hydrogen gas was produced by the reaction of the zinc and hydrochloric acid. Hydrogen in
the presence of fire can be combustible. 

C. What gas was produced by the decomposition of hydrogen peroxide? What happened
when the smoldering toothpick came in contact with the gas?
Hydrogen was produced by the decomposition of the hydrogen peroxide. When the smoldering toothpick contacted the gas particles heat is produced.

D. Compare the behavior of the mixture of gases with each solitary gas in the presence of
flame  

Mixture of gases in turn produces a lessened amount heat or light. But solitary gases

produce a high amount of heat or light. 

E. Outline the procedures you would use to determine whether a gas sample was composed
of hydrogen or oxygen.
If we have a gas sample and flame, then hydrogen can be determined as we heard a
popping noise. So of determining the presence of oxygen, we use smoldering toothpick
with the gas sample. Exercise 2: Gas and Reactions
Data Table 2. Carbon Dioxide Reaction Observations.
Reaction
Ca(OH)2 + CO2
CO2 + BTB
CO2 + Flame
Ca(OH)2 + Antacid/water gas
Antacid/water gas + Smoldering toothpick
Ca(OH)2 + Breath Observations
Cloudy and white solution with bubbles
created as a result of the gases from
dissolving baking soda.
Formed carbonic acid, indicator turns dark
blue to yellowish brown
Flame was extinguished
Creation of a cloudy white solution with
bubbles
No reaction seen
Cloudy white in color Questions

A. The chemical equation for the reaction of baking soda (sodium bicarbonate, NaHCO3) and
vinegar (acetic acid, CH3COOH) may be written as two steps. Fill in the missing information for
the chemical equation.
Step 1: NaHCO3 (s) + CH3COOH (aq) CH3COONa (aq) + H2CO3 (l)
Step 2: H2CO3 (l) H2O (l) + CO2 (g) 

B. Write a chemical equation for the reaction of CO2 and limewater (Ca(OH)2). Write a physical
description of the products formed.
Ca(OH)2 (aq) +CO2 (g) ---- CaCO3 (s) +H2O (aq)
Product formed CaCO3, this is a solid and white in color. H2O is water. 

C. When the bromothymol blue (BTB) was exposed to the CO2 gas, what color was the solution?
Did the BTB indicate presence of an acid or base? Explain your answer.
When the solution containing CO2 is bubbled through the BTB, carbonic acid is formed
as a result. This gives us a color change from a blue to a yellowish brown color

 D. Did the reaction between the antacid tablet and the tap water produce hydrogen, oxygen, or
carbon dioxide gas? Support your answer with results from your work in both Exercise 1 and

Exercise 2.
3HCO3- + 3h+---- 6H+3O+3CO2
E. Based on your observation of the reaction that occurred when limewater was exposed to your
breath, what gas did you exhale? Support your answer with your observations in Data Table 2.
Though we know that we exhale CO2 just as majority of earth multicellular organisms do we in
fact exhale about 18% O2, 78% N2, and 4.0% CO2. That being said when I exhaled through the
straw I was adding these chemicals to the mixtures.