The portal has been deactivated. Please contact your portal admin.

Lesson Worksheet: Tests for Gases and Water Chemistry

In this worksheet, we will practice using qualitative chemical tests to identify water and 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?

  • AMgBr
  • BHO2
  • CLiCl
  • DKO2
  • ENaOH

Q5:

A student wants to test if a liquid contains any water.

Which of the following substances can the student use?

  • AAnhydrous calcium chloride
  • BAnhydrous iron(III) chloride
  • CAnhydrous phosphorus pentoxide
  • DAnhydrous zinc(II) sulfate
  • EAnhydrous copper(II) sulfate

How will the student know if water is present?

  • AThe calcium chloride will change color from white to yellow.
  • BThe zinc(II) sulfate will change color from red to brown.
  • CThe phosphorus pentoxide will change color from white to grey.
  • DThe copper(II) sulfate will change color from white to blue.
  • EThe iron(III) chloride will change color from yellow to pink.

Q6:

In an experiment, the electrolysis of water was carried out and two gases were collected in test tubes A and B. It was found that the gas in test tube A produced a flash and a loud popping sound when a lit splint was placed at the opening. The gas in test tube B was found to relight a glowing splint. What gases are in each test tube?

  • AA: hydrogen, B: chlorine
  • BA: oxygen, B: hydrogen
  • CA: hydrogen, B: oxygen
  • DA: carbon dioxide, B: oxygen
  • EA: carbon dioxide, B: hydrogen

Q7:

Although normally unreactive to acids, copper will react with hot, concentrated sulfuric acid according to the equation shown: Cu()+HSO()2HO()+SO()+CuSO()saqlgaq24224 To test for SO2 gas, a piece of filter paper was soaked in acidified aqueous potassium manganate(VII) and held over the reaction mixture. What color change should occur?

  • ABlue to yellow
  • BPurple to red
  • CGreen to purple
  • DPurple to colorless
  • ERed to green

Q8:

A gas is produced by a chemical reaction. When moist red litmus paper was held to the opening of the test tube, a color change to blue was observed. The gas also had a very strong smell.

What is the probable identity of the gas?

  • AHydrogen
  • BAmmonia
  • CCarbon monoxide
  • DCarbon dioxide
  • EOxygen

Which of the following reactions would produce this gas?

  • AAmmonium chloride + calcium hydroxide
  • BDecomposition of hydrogen peroxide
  • CCarbon dioxide + carbon
  • DCalcium carbonate + hydrochloric acid
  • ENitric acid + magnesium

Q9:

In an experiment, NaCl was reacted with HSO24 to produce a salt and a gas. The gas produced was subjected to various tests, which are shown below. By considering the products of the reaction, what is the probable identity of the gas?

TestMoist blue litmus paperBubbling through limewaterGlowing splint held to the gasLit splint held to the gasFilter paper soaked in acidified aqueous potassium manganate(VII) held to the gasMoist red litmus paper
ObservationThe color changed from blue to red.The solution remained colorless.The splint did not relight.The splint was extinguished.The filter paper remained purple in color.No color change was observed.
  • AH2
  • BHCl
  • CO2
  • DSO3
  • ESO2

Q10:

In an experiment, pieces of zinc metal were reacted with hydrochloric acid, producing a salt and a gas. This gas was found to be lighter than air.

Which diagram shows a piece of equipment that could not be used to collect this gas?

  • A
  • B
  • C
  • D

What test would confirm the presence of the gas produced in this reaction?

  • AMoist blue litmus paper, which would turn red and then white
  • BA glowing splint, which would relight
  • CMoist red litmus paper, which would turn blue
  • DBubbling the gas through limewater, which would turn cloudy
  • EA lit splint, which would produce a flash and a popping sound

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.