Chemical Reactions and Equations Quiz

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Questions and Answers

What happens to the magnesium ribbon when it is burned?

It turns into a gas.
It melts into liquid metal.
It produces a black powder.
It burns with a dazzling white flame. (correct)

A chemical reaction can occur without a change in the identity of the substance.

False (B)

What is the product formed when magnesium burns in air?

Magnesium oxide

When food is digested in our body, it undergoes a __________ change.

chemical Signup and view all the answers

Match the following activities with the substances involved:

Burning magnesium ribbon = Magnesium oxide Fermentation of grapes = Alcohol Cooking food = Chemical change Respiration = Energy release Signup and view all the answers

Which of the following scenarios is an example of a chemical change?

Fermentation of grapes (B) Signup and view all the answers

Cooking food is an example of a physical change.

False (B) Signup and view all the answers

What substance is produced when lead nitrate is involved in a chemical reaction?

Potassium lead or lead(II) oxide Signup and view all the answers

What is indicated by a change in temperature during a chemical reaction?

That a chemical reaction has occurred (D) Signup and view all the answers

A word-equation shows both reactants and products separated by a plus sign.

False (B) Signup and view all the answers

What are the substances that undergo chemical change in a reaction called?

Reactants Signup and view all the answers

Magnesium burned in oxygen produces __________.

magnesium oxide Signup and view all the answers

Match the following terms with their correct descriptions:

Reactants = Substances that undergo chemical change Products = New substances formed from a reaction Word-equation = Representation of a chemical reaction in words Chemical reaction = Process that leads to the transformation of substances Signup and view all the answers

Which of the following is NOT a sign that a chemical reaction has taken place?

Reappearance of reactants (A) Signup and view all the answers

Chemical reactions can only occur in a closed system.

False (B) Signup and view all the answers

The arrow in a word-equation indicates the direction of the __________.

reaction Signup and view all the answers

What gas is emitted when lead nitrate is heated?

Nitrogen dioxide (B) Signup and view all the answers

The decomposition of lead nitrate produces only solid lead oxide.

False (B) Signup and view all the answers

What is the primary purpose of adding dilute sulfuric acid in the electrolysis of water experiment?

To increase the conductivity of water Signup and view all the answers

The chemical reaction for the decomposition of lead nitrate is represented as: 2Pb(NO3)2(s) ______________ 2PbO(s) + 4NO2(g) + O2(g).

heat Signup and view all the answers

Match the following components of the electrolysis setup with their functions:

Carbon electrodes = Conduct electricity through water Water = Medium for electrolysis Battery = Supplies electrical energy Rubber stoppers = Prevent water leakage Signup and view all the answers

During the electrolysis experiment, what happens to the gases formed at the electrodes when a burning candle is brought near them?

They produce a popping sound (A), They extinguish the candle (D) Signup and view all the answers

The amount of gas collected at both electrodes during electrolysis is expected to be equal.

False (B) Signup and view all the answers

What observation is noted when lead nitrate is heated?

Emission of brown fumes Signup and view all the answers

What happens during the reaction between copper(II) oxide and hydrogen gas?

Copper(II) oxide is reduced. (D) Signup and view all the answers

In a redox reaction, one reactant is always reduced and the other is always oxidized.

True (A) Signup and view all the answers

What is the product formed when copper combines with oxygen?

Copper(II) oxide (CuO) Signup and view all the answers

In a reaction, if a substance loses oxygen, it is said to be __________.

reduced Signup and view all the answers

Match the following reactions with their corresponding processes:

Cu + O2 → CuO = Oxidation of copper CuO + H2 → Cu + H2O = Reduction of copper(II) oxide ZnO + C → Zn + CO = Reduction of zinc oxide MnO2 + 4HCl → MnCl2 + 2H2O + Cl2 = Oxidation of hydrochloric acid Signup and view all the answers

Which statement is true regarding oxidation?

A substance gaining oxygen is oxidized. (D) Signup and view all the answers

In the reaction ZnO + C → Zn + CO, carbon is reduced.

False (B) Signup and view all the answers

During the burning of magnesium in air, what type of reaction occurs?

Oxidation Signup and view all the answers

What is the reddish-brown coating that forms on iron over time called?

Rusting (B) Signup and view all the answers

Corrosion only affects iron and no other metals.

False (B) Signup and view all the answers

What is the process called when fats and oils become rancid?

Oxidation Signup and view all the answers

The green coating formed on copper due to corrosion is known as __________.

verdigris Signup and view all the answers

Match the following terms with their definitions:

Corrosion = The process of metals being damaged by their environment Rancidity = The unpleasant smell and taste from oxidized fats Antioxidants = Substances that prevent oxidation Tarnishing = The discoloration of metals due to oxidation Signup and view all the answers

Why do manufacturers flush bags of chips with nitrogen?

To prevent oxidation (C) Signup and view all the answers

Identify one effect of corrosion on everyday objects.

Damage to car bodies Signup and view all the answers

Keeping food in airtight containers can help slow down rancidity.

True (A) Signup and view all the answers

What are the products formed when hydrogen sulphide gas burns in air?

Water and sulfur dioxide (A) Signup and view all the answers

Zinc carbonate decomposes to form zinc oxide and carbon dioxide.

True (A) Signup and view all the answers

What is considered an endothermic reaction?

A reaction that absorbs heat from its surroundings. Signup and view all the answers

The process of __________ involves a single replacement of elements in a chemical reaction.

displacement Signup and view all the answers

Match the following types of reactions with their examples:

Combination reaction = A + B → AB Decomposition reaction = AB → A + B Displacement reaction = A + BC → AC + B Precipitation reaction = AB(aq) + CD(aq) → AD(s) + CB(aq) Signup and view all the answers

Which of the following reactions is an example of a double displacement reaction?

Barium chloride + Potassium sulfate → Barium sulfate + Potassium chloride (C) Signup and view all the answers

Respiration is classified as a decomposition reaction.

True (A) Signup and view all the answers

What characterizes an exothermic reaction?

Exothermic reactions release heat into the surroundings. Signup and view all the answers

Flashcards

Chemical Reaction

A process where the nature and identity of substances change.

Chemical Change

A reaction where the composition of the substance alters.