Nuri was doing an experiment. He has noted his observation in a table. Methods Observation Add 1 drop of sodium hydroxide to calcium chloride A white solid appeared. Write a word equation for the reaction.

Sodium hydroxide when reacts with calcium chloride undergoes a double displacement reaction and forms a white solid calcium hydroxide and a solution of sodium chloride. The word equation for the reaction is as follows: sodium hydroxide + calcium chloride → calcium hydroxide + sodium chloride

Nuri was doing an experiment. He has noted his observation in a table. Methods Observation Heat copper metal in a flame The metal went black Write a word equation for the reaction.

When copper metal is heated in a flame it reacts with oxygen and gets oxidised, and forms copper oxide. The black layer of copper oxide is observed on the surface of the metal. The word equation for the reaction is as follows: copper + oxygen → copper oxide

Nuri was doing an experiment. He has noted his observation in a table. Methods Observation Add copper metal to hydrochloric acid. No changes observed. Write a word equation for the reaction.

Copper is the less reactive metal and is placed below hydrogen in a reactivity series. It does not show any displacement reaction. The word equation for the reaction is as follows: copper metal + hydrochloric acid → no change

Nuri was doing an experiment. He has noted his observation in a table. Methods Observation Add magnesium metal to hydrochloric acid. Bubbles are seen coming off of the metal. Write a word equation for the reaction.

Magnesium is a reactive metal and is placed above the hydrogen in a reactivity series. It displaces hydrogen from the acid and forms magnesium chloride. The word equation for the reaction is as follows: magnesium + hydrochloric acid → magnesium chloride + hydrogen gas

When sodium hydroxide is added to a solution of iron (lll) chloride, the following can be seen: A rust coloured solid is formed. The total mass does not change. Explain the observations. Your answer should include a word equation.

Sodium hydroxide and iron III oxide react together and forms rust-coloured iron hydroxide and a sodium sulphate solution. The word equation for the reaction is as follows: sodium hydroxide + iron III sulphate → iron hydroxide + sodium sulphate Chemical reactions follow the law of conservation of mass. The law states that in a chemical reaction the mass of the products formed is equal to the mass of reactants. Hence, the mass total mass does not change, and it is conserved. The total mass of sodium hydroxide and iron III oxide = The total mass of sodium sulphate and iron hydroxide.

MEDIUM

Lower Secondary Stage 8

IMPORTANT

Earn 100

Nuri was doing an experiment. He has noted his observation in a table.

Methods Observation

Add $1$ drop of sodium hydroxide to iron (lll) sulphate
A rust-coloured solid appeared.

Write a word equation for the reaction.

Important Questions on Chemical Reactions

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Workbook>Chapter 6 - Chemical Reactions>Exercise 1>Q 10

Nuri was doing an experiment. He has noted his observation in a table.

Methods	Observation
Add $1$ drop of sodium hydroxide to calcium chloride	A white solid appeared.

Write a word equation for the reaction.

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Workbook>Chapter 6 - Chemical Reactions>Exercise 1>Q 10

Nuri was doing an experiment. He has noted his observation in a table.

Methods	Observation
Heat copper metal in a flame	The metal went black

Write a word equation for the reaction.

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Workbook>Chapter 6 - Chemical Reactions>Exercise 1>Q 10

Nuri was doing an experiment. He has noted his observation in a table.

Methods	Observation
Add copper metal to hydrochloric acid.	No changes observed.

Write a word equation for the reaction.

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Workbook>Chapter 6 - Chemical Reactions>Exercise 1>Q 10

Nuri was doing an experiment. He has noted his observation in a table.

Methods	Observation
Add magnesium metal to hydrochloric acid.	Bubbles are seen coming off of the metal.

Write a word equation for the reaction.

MEDIUM

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Workbook>Chapter 6 - Chemical Reactions>Exercise 1>Q 11

When sodium hydroxide is added to a solution of iron (lll) chloride, the following can be seen:

A rust coloured solid is formed.
The total mass does not change.

Explain the observations. Your answer should include a word equation.

MEDIUM

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Workbook>Chapter 6 - Chemical Reactions>Exercise 2>Q 1

Name the compounds produced when hydrochloric acid reacts with calcium oxide.

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Workbook>Chapter 6 - Chemical Reactions>Exercise 2>Q 4

When zinc metal was added to some sulphuric acid, small bubbles of gas were observed. Describe a test that would show if the gas produced was hydrogen.

HARD

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Workbook>Chapter 6 - Chemical Reactions>Exercise 2>Q 5

Explain what is meant by the statement:

“New compounds are formed during a chemical reaction.”

Give an example in your answer.

Methods	Observation
Add $1$ drop of sodium hydroxide to iron (lll) sulphate	A rust-coloured solid appeared.

Nuri was doing an experiment. He has noted his observation in a table. Methods Observation Add 1 drop of sodium hydroxide to iron (lll) sulphate A rust-coloured solid appeared. Write a word equation for the reaction.

Important Questions on Chemical Reactions

Learn and Prepare for any exam you want !

Nuri was doing an experiment. He has noted his observation in a table.

Methods Observation

Add $1$ drop of sodium hydroxide to iron (lll) sulphate
A rust-coloured solid appeared.

Write a word equation for the reaction.