LAB: IDENTIFYING MYSTERY GASES
Air is made up of a mixture of many gases, including nitrogen, oxygen, carbon dioxide and hydrogen. Most of these
gases are colourless, odourless, and transparent, making them difficult to distinguish from one another. So how can we
tell them apart?
Different gases exhibit different chemical properties, such as reactivity with other chemical substances. These chemical
properties are like fingerprints and allow for a gas' identity to be discovered.
Pre-Lab :
Make sure to read the lab procedure on page 270-271 before answering the Pre-Lab questions.
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Answer all questions in the space provided below.
1. In your own words, what is the reason or purpose behind this lab?
2 marks
To answer the next three questions, please go to the class website (sciencemrluth.weebly.com) under the SNC1D/Chemistry tab
and watch the video ‘Gas Tests’:
2. How did the presenter identify oxygen gas? 1 mark
3. How did the presenter identify hydrogen gas? 1 mark
4. How did the presenter identify carbon dioxide gas? 1 mark
Complete the following:
Oxygen Test
The splint should be…
burning
glowing
(circle one)
3 marks
If oxygen is present, the splint will: ____________________________________
What chemical property of oxygen allows you to identify it? ____________________________________
Hydrogen Test
The splint should be…
burning
glowing
(circle one)
3 marks
If hydrogen is present, what will happen? ____________________________________
What chemical property of hydrogen are you testing for? ____________________________________
Carbon Dioxide
The splint should be…
burning
glowing
(circle one)
4 marks
If you put a burning splint into carbon dioxide, what will happen? ___________________________________
The chemical test for carbon dioxide uses a liquid called ___________________________________________
A positive test for carbon dioxide, means the limewater will look ____________________________________
PURPOSE:
How can you test for oxygen, carbon dioxide, and hydrogen gas produced in chemical reactions?
MATERIALS:
Goggles
4 test tubes
test-tube rack
hydrogen peroxide solution
manganese dioxide powder
toothpick
3 wooden splints
Hydrochloric acid solution
Magnesium ribbon
Test-tube stopper
candle
sodium bicarbonate powder
SAFETY PRECAUTIONS:


Hydrochloric acid is corrosive. Any spills on the skin, in the eyes, on clothing should be washed immediately with
cold water. Report any spills to your teacher.
Hydrogen peroxide is a strong irritant. Do not get in eyes. Manganese dioxide is also toxic. Report any spills to your
teacher.
PROCEDURE: REFER TO ‘SCIENCE 9 PERSPECTIVES TEXTBOOK’ ON PAGE 270-271
Waste Disposal:
Dispose of all mixtures into the waste containers provided at the end of the lab benches. Clean up your workstation, put
away all materials and wash your hands.
DISCUSSION QUESTIONS:
Answer the following questions using complete sentences, if necessary.
1. In a chart format, two physical properties and two chemical properties for each gas produced in this lab.
2. Why did you record your observations before proceeding with each chemical reaction?
3. Which gas seemed to be the most hazardous in this activity? Why?
Observations
Table 1: (descriptive title)
_______________________________________________________________________________________________________________________
STARTING SUBSTANCES (REACTANTS)
PART
NAME
Potassium Iodide
powder
1
Manganese
Dioxide powder
Hydrogen
Peroxide
Hydrochloric acid
2
Sodium hydrogen
carbonate powder
(Baking soda)
limewater
Hydrochloric
Acid
3
Mossy zinc OR
Magnesium
metal
PROPERTIES (AT LEAST 3)
OBSERVATIONS AFTER MIXING
(AT LEAST 2)
WHAT HAPPENS WHEN THE STARTING
MATERIALS ARE ADDED TOGETHER?
RESULTS OF BURNING
SPLINT TEST
RESULT OF GLOWING
SPLINT TEST
RESULT OF
LIMEWATER TEST
NOTES
1. Using the chart below, state two physical properties and two chemical properties for each gas produced in this lab.
Gas
Physical Properties
2. What problems, if any, did you encounter in carrying out each of these tests?
3. Which gas seemed to be the most hazardous in this activity? Why?
4. What improvements, if any, would you make to the procedure in future tests?
Chemical Properties