Worksheet: Identifying Gases

In this worksheet, we will practice using qualitative chemical tests to identify common gases, including hydrogen, oxygen, carbon dioxide, and chlorine.

Q1:

A student uses a test tube to collect the gas produced by a chemical reaction. After lighting a splint, they blow out the flame and then insert the splint into the test tube. It reignites and glows brightly.

What is the probable identity of the gas?

  • AHydrogen
  • BAmmonia
  • CCarbon dioxide
  • DOxygen
  • EChlorine

Why does the splint glow more brightly than it did when burning in air?

  • ABecause the gas is burning too
  • BBecause the gas catalyzes the combustion of the splint
  • CBecause the gas is forming a plasma
  • DBecause it is burning faster

Which of the following reactions could have produced the gas?

  • AAluminum chloride + sodium hydroxide
  • BZinc + sulfuric acid
  • CBarium carbonate + nitric acid
  • DHydrogen peroxide with manganese oxide catalyst
  • ESilver oxide + hydrochloric acid

Q2:

A student uses a test tube to collect the gas produced by a chemical reaction. When a lit splint is placed at the opening of the test tube, there is a brief flash and a loud popping sound. In addition, fine droplets of colorless liquid are formed on the inside of the tube.

What is the probable identity of the gas?

  • AOxygen
  • BAmmonia
  • CCarbon dioxide
  • DHydrogen
  • EMethane

What is the probable identity of the colorless liquid?

  • ALiquid carbon dioxide
  • BOil
  • CAmmonia solution
  • DEthanol
  • EWater

Which of the following reactions could have produced the gas?

  • ASodium hydroxide + water
  • BLithium oxide + sulfuric acid
  • CZinc + hydrochloric acid
  • DZinc + copper(II) sulfate
  • EMagnesium carbonate + heat

Q3:

A gas is produced by a chemical reaction. The gas is identified by passing it through a tube into a flask of limewater.

What is the probable identity of the gas?

  • AAmmonia
  • BCarbon dioxide
  • CHydrogen
  • DOxygen
  • EChlorine

Which chemical is responsible for the cloudy appearance of the solution?

  • ACalcium hydride
  • BCalcium chloride
  • CCalcium
  • DCalcium oxide
  • ECalcium carbonate

Which of the following reactions could have produced the gas?

  • AHydrogen peroxide + manganese oxide catalyst
  • BCalcium oxide + heat
  • CSodium carbonate + hydrochloric acid
  • DSilver chloride + zinc
  • EAmmonium hydroxide + sodium hydroxide

Which of the following substances could be added to the cloudy limewater to produce a clear solution?

  • ACalcium hydroxide
  • BHydrochloric acid
  • CHydrogen peroxide
  • DCalcium chloride
  • EOxygen

Q4:

During an electrolysis experiment, a student uses a test tube to collect a colored gas generated at the anode. When wet blue litmus paper is pressed to the opening of the test tube, a color change to red is observed. After a few seconds, the litmus paper turns white.

What is the probable identity of the gas?

  • AAmmonia
  • BOxygen
  • CChlorine
  • DWater
  • EHydrogen

What is indicated by the change in color of the litmus paper from blue to red?

  • AThe gas has dissolved.
  • BAn acid has been produced.
  • CThe gas is unreactive.
  • DThe gas has decomposed.
  • EAn alkali has been produced.

What is indicated by the change in color of the litmus paper from red to white?

  • AA very strong acid has been produced.
  • BThe litmus paper is defective.
  • CAn alkali has been produced.
  • DA bleach has been produced.
  • EThe gas is unreactive.

From which of the following dissolved substances could the colored gas have been produced?

  • A M g B r
  • B H O 2
  • C L i C l
  • D K O 2
  • E N a O H

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