Chemistry Chapter on Reactions and Electrolysis

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Questions and Answers

What is the primary characteristic of an exothermic reaction?

It transfers thermal energy to the surroundings. (correct)

It results in a decrease in the temperature of the surroundings.

It requires a catalyst to proceed.

It absorbs thermal energy from the surroundings.

What is the sign of the enthalpy change (∆H) for an endothermic reaction?

Positive (correct)

Varies depending on the reaction

Negative

Zero

Which of the following statements is true regarding activation energy (Ea)?

It is the total energy available in a chemical reaction.

It decreases as the concentration of reactants increases.

It is the energy required for particles to collide effectively. (correct)

It is the energy released during a reaction.

How is bond breaking characterized in terms of energy?

It is an endothermic process that absorbs energy. Signup and view all the answers

When calculating the enthalpy change of a reaction using bond energies, which process is considered exothermic?

The energy released during bond formation. Signup and view all the answers

During the electrolysis of molten lead(II) bromide, which substance is produced at the cathode?

Lead Signup and view all the answers

In the electrolysis of concentrated aqueous sodium chloride, which product is formed at the anode?

Chlorine gas Signup and view all the answers

What is formed at the cathode during the electrolysis of dilute sulfuric acid?

Hydrogen gas Signup and view all the answers

In the electrolysis of a binary compound, what is produced at the anode?

Non-metal elements Signup and view all the answers

What purpose does electroplating serve for metal objects?

To improve appearance and resistance to corrosion Signup and view all the answers

Which statement correctly describes hydrogen–oxygen fuel cells?

They require oxygen and produce electricity with water as the only chemical product Signup and view all the answers

Which of the following is NOT a product of the electrolysis of aqueous copper(II) sulfate using copper electrodes?

Hydrogen gas Signup and view all the answers

What change occurs to the appearance of metal objects during electroplating?

They gain a shiny finish Signup and view all the answers

Which chemical test confirms the presence of water by changing from blue to pink?

Anhydrous cobalt(II) chloride Signup and view all the answers

What is the purpose of chlorination in the treatment of domestic water supply?

To kill harmful microbes Signup and view all the answers

Why is distilled water preferred over tap water in practical chemistry?

It has fewer chemical impurities Signup and view all the answers

Which harmful substance may be present in natural water sources that can lead to diseases?

Sewage Signup and view all the answers

What negative impact do nitrates and phosphates have on aquatic life?

They lead to deoxygenation of water Signup and view all the answers

What role does carbon play in the treatment of domestic water?

To remove tastes and odors Signup and view all the answers

Which of the following substances is typically beneficial in water sources?

Some metal compounds Signup and view all the answers

Which method is used to remove solids from the domestic water supply?

Filtration Signup and view all the answers

Which substance is NOT a potential pollutant in natural water sources?

Dissolved oxygen Signup and view all the answers

What is the first step in the treatment of the domestic water supply?

Sedimentation Signup and view all the answers

What is the main ore of aluminium that is commonly used for extraction?

Bauxite Signup and view all the answers

Which process is primarily used to extract aluminium from bauxite?

Electrolysis Signup and view all the answers

Why must the carbon anodes in the electrolysis process be regularly replaced?

They are oxidized and consumed during the reaction. Signup and view all the answers

What role does cryolite play in the extraction of aluminium?

It lowers the melting point of alumina. Signup and view all the answers

During the electrolysis of aluminium oxide, what occurs at the cathode?

Aluminium ions are reduced to form aluminium metal. Signup and view all the answers

What is the result of the thermal decomposition of calcium carbonate in the extraction process?

Production of carbon dioxide and calcium oxide. Signup and view all the answers

What is the reaction that takes place when carbon dioxide is reduced to carbon monoxide during iron extraction?

C + CO2 → 2CO Signup and view all the answers

What is the term for the compound formed when calcium oxide reacts with silicon dioxide?

Calcium silicate Signup and view all the answers

In the electrolysis of aluminium oxide, which product is formed at the anode?

Oxygen gas Signup and view all the answers

What is the primary purpose of the extraction processes for aluminium and iron?

To obtain metals from their ores economically. Signup and view all the answers

What is defined as the decomposition of an ionic compound by the passage of an electric current?

Electrolysis Signup and view all the answers

Which electrode is known as the positive electrode in an electrolytic cell?

Anode Signup and view all the answers

During electrolysis, what happens to electrons at the anode?

Loss of electrons Signup and view all the answers

What movement occurs within the electrolyte during electrolysis?

Movement of ions Signup and view all the answers

In the context of electrolysis, what is the electrolyte primarily composed of?

Molten or aqueous ionic substances Signup and view all the answers

What is the main function of the cathode in an electrolytic cell?

To gain electrons and facilitate reduction Signup and view all the answers

Which of the following activities occurs at the cathode during electrolysis?

Reduction of cations Signup and view all the answers

Which statement correctly describes the overall process during electrolysis?

Electric current decomposes ionic compounds Signup and view all the answers

What is required for electrolysis to take place?

Electric current and an ionic compound Signup and view all the answers

What is the role of the electric current in an electrolytic cell?

To provide energy for ionic decomposition Signup and view all the answers

Study Notes

Syllabus Overview

The syllabus is for IGCSE Chemistry (0620)
Exams are available in 2023, 2024, and 2025
Exams are offered in the June and November series
Exams are also available in the March series in India only

Aims

Enable students to acquire scientific knowledge and understanding of scientific theories and practice
Develop experimental skills, including handling variables and working safely
Use scientific data and evidence to solve problems and discuss limitations of scientific methods
Communicate effectively, using scientific terminology, notation, and conventions
Understand that scientific knowledge can benefit people and the environment
Enjoy science and develop an informed interest in scientific matters

Content Overview

States of matter
Atoms, elements, and compounds
Stoichiometry
Electrochemistry
Chemical energetics
Chemical reactions
Acids, bases, and salts
The Periodic Table
Metals
Chemistry of the environment
Organic chemistry
Experimental techniques and chemical analysis

Assessment Overview

All candidates take three papers.
Core candidates take Paper 1 (Multiple Choice), Paper 3 (Theory) and either Paper 5 (Practical Test) or Paper 6 (Alternative to Practical)
Extended candidates take Paper 2 (Multiple Choice), Paper 4 (Theory) and either Paper 5 or Paper 6

Assessment Objectives

AO1: Knowledge with understanding (50%)
AO2: Handling information and problem-solving (30%)
AO3: Experimental skills and investigations (20%)

Mathematical Requirements

Calculations may be used in all parts of the examination.
Including operations with numbers, decimals, fractions, percentages, ratios, standard forms, etc.
Algebraic manipulation and solving simple equations.
Using graphs and charts (interpolation and extrapolation for example.)
Calculating gradients and intercepts of lines on graphs.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your understanding of key chemistry concepts related to exothermic and endothermic reactions, activation energy, and electrolysis processes. This quiz covers important principles and experimental outcomes relevant to the study of chemical reactions. Challenge yourself with questions about bond energies and the products of various electrolysis reactions.