3.Chemical Reactions and Equations | 10th Class Science I | Question and Answers | Lesson No. 3

Summary

This educational video script offers a comprehensive lesson on chemical reactions and equations for class 10 science students. It covers concepts such as oxidation, reduction, electrolysis, and displacement reactions, with examples and explanations. The script delves into galvanization to prevent rusting, the role of catalysts in speeding up reactions, and the importance of balanced equations. It also discusses factors affecting reaction rates and the significance of storing substances properly to prevent oxidation. The engaging content is designed to clarify complex chemical principles and encourage students to explore further.

Takeaways

• 📚 The video covers chemical reactions and equations from a Class 10 science textbook, focusing on various types of reactions and their explanations.
• 🛡️ Galvanization is the process of coating iron with zinc to prevent rusting, which is an oxidation reaction where iron reacts with oxygen to form iron oxide (rust).
• 🔋 Electrolysis is the process of decomposing water into hydrogen and oxygen gases using electrical energy.
• 🔄 Double displacement reactions involve the exchange of ions between reactants to form a precipitate, like the reaction between zinc sulfate and barium chloride.
• 🔄 Redox reactions are those where oxidation and reduction occur simultaneously, such as the reaction between sulfur dioxide and hydrogen sulfide.
• ⏱️ The rate of chemical reactions, like the decomposition of hydrogen peroxide, can be increased by using a catalyst, such as manganese dioxide.
• 🔬 Reactants are the substances that undergo chemical reactions, and products are the new substances formed as a result.
• ⚔️ Oxidation reactions involve a substance combining with oxygen or losing hydrogen, while reduction reactions involve a substance combining with hydrogen or losing oxygen.
• 🌡️ Endothermic reactions absorb heat from the surroundings, like the melting of ice, whereas exothermic reactions release heat, such as the neutralization reaction between hydrochloric acid and sodium hydroxide.
• 🔄 Combination reactions occur when two or more reactants combine to form a single product, exemplified by the burning of magnesium in air to form magnesium oxide.
• ⚖️ Balanced chemical equations ensure that the number of atoms for each element is conserved between reactants and products, following the law of conservation of mass.

Q & A

What is the process called when a thin coating of zinc is applied on iron to prevent rusting?

The process is called galvanization. It involves applying a layer of zinc on iron sheets to prevent them from coming in direct contact with the atmosphere, thus preventing rusting.

What is the chemical formula of rust that forms on iron surfaces?

The chemical formula of rust is iron(III) oxide, hydrated, often denoted as Fe2O3·nH2O, where n represents the variable number of water molecules.

What is an oxidation reaction in the context of the conversion of ferrous sulfate to ferric sulfate?

An oxidation reaction is characterized by the loss of electrons. In the case of ferrous sulfate converting to ferric sulfate, the ferrous ion (Fe2+) loses an electron to become the ferric ion (Fe3+), which is an example of an oxidation process.

What is electrolysis and how does it relate to the decomposition of water?

Electrolysis is a process that uses electrical energy to cause a non-spontaneous chemical reaction. In the context of water decomposition, when electric current is passed through acidulated water, it breaks down into hydrogen and oxygen gases, which is an example of electrolysis.

What is a double displacement reaction and how is it exemplified when zinc sulfate solution is added to barium chloride solution?

A double displacement reaction occurs when the ions in the reactants exchange places to form new compounds. When zinc sulfate solution is added to barium chloride solution, a reaction occurs forming zinc chloride and a white precipitate of barium sulfate, which is an example of a double displacement reaction.

What is a redox reaction and how is it demonstrated in the reaction between sulfur dioxide and hydrogen sulfide?

A redox reaction is a chemical reaction where oxidation and reduction occur simultaneously. In the reaction between sulfur dioxide and hydrogen sulfide, sulfur dioxide is reduced while hydrogen sulfide is oxidized, demonstrating a redox reaction.

How can the rate of decomposition of hydrogen peroxide be increased?

The rate of decomposition of hydrogen peroxide can be increased by adding manganese dioxide powder, which acts as a catalyst to speed up the reaction without being consumed in the process.

What are reactants and products in a chemical reaction, and how do they differ?

Reactants are the substances that participate in a chemical reaction, undergoing bond breaking. Products are the new substances formed as a result of the reaction, with new bonds formed. They differ in that reactants are the starting materials, while products are the end result of the reaction.

What is the difference between oxidation and reduction reactions with respect to oxygen and hydrogen?

Oxidation reactions involve a reactant combining with oxygen or losing hydrogen to form a product. Reduction reactions, on the other hand, involve a reactant combining with hydrogen or losing oxygen to form a product.

What are the similarities and differences between adding sodium (Na) to water and adding calcium (Ca) to water?

Both Na and Ca dissolve in water to form basic solutions, turning red litmus paper blue and are exothermic reactions. The differences include Na forming a highly soluble sodium hydroxide solution, which is monovalent, whereas Ca forms a less soluble calcium hydroxide solution, which is divalent.

What is an endothermic reaction and how is it related to the melting of ice or dissolution of potassium nitrate in water?

An endothermic reaction is a process that absorbs heat from the surroundings. The melting of ice and the dissolution of potassium nitrate in water are examples of endothermic processes because they absorb heat, resulting in a decrease in the temperature of the solution.

What is a combination reaction and how is it exemplified by the burning of a magnesium strip in air?

A combination reaction is a chemical reaction where two or more reactants combine to form a single product. The burning of a magnesium strip in air is an example, where magnesium combines with oxygen to form magnesium oxide.

Why is it recommended to store oil in airtight containers for a long time?

It is recommended to store oil in airtight containers to prevent oxidation, which can cause the oil to become rancid. Exposure to air, heat, and light enhances the oxidation process, so airtight containers help maintain the quality of the oil.

What happens when concentrated sulfuric acid is added to water and why should it be done slowly with constant stirring?

When concentrated sulfuric acid is added to water, a large amount of heat is liberated due to the exothermic reaction. Since concentrated sulfuric acid is denser than water and highly corrosive, adding it slowly with constant stirring prevents the water from evaporating rapidly and avoids the splashing of acid, which could cause accidents.

What is the significance of the balanced equation in a chemical reaction?

A balanced equation ensures that the number of atoms of each element is the same on both sides of the equation, in accordance with the law of conservation of mass. This means that the total mass of each element in the reactants is equal to the total mass of each element in the products.

What is a displacement reaction and how does it differ from other types of reactions?

A displacement reaction occurs when a more reactive element displaces a less reactive element in a compound, forming its own ions. This differs from other reactions as it involves a direct exchange of ions between the reactants, leading to the formation of new elements and compounds.

Outlines

00:00

🔍 Chemistry Lesson Overview

This paragraph introduces a chemistry lesson focused on chemical reactions and equations from a Class 10 science textbook. It outlines the lesson's content, including oxidation, displacement, electrolysis, reduction, and double displacement reactions. The paragraph also discusses the concept of galvanization as a rust prevention method and explains the oxidation of iron to form rust. Additionally, it covers the electrolysis of water and the formation of hydrogen and oxygen gases, as well as the double displacement reaction between zinc sulfate and barium chloride.

05:01

🧪 Types of Chemical Reactions

The second paragraph delves into the types of chemical reactions, specifically oxidation and reduction, with examples provided for each. It explains the concept of redox reactions where oxidation and reduction occur simultaneously. The paragraph also discusses how the rate of a chemical reaction, such as the decomposition of hydrogen peroxide, can be increased by using a catalyst like manganese dioxide. Furthermore, it defines reactants and products in a chemical reaction and illustrates this with the combustion of coal and the reaction between copper sulfate and zinc.

10:03

🔬 Understanding Chemical Reactions and Catalysts

This section explains the terms 'reactant' and 'product' with examples, emphasizing the transformation of substances during chemical reactions. It also discusses the types of reactions involving oxygen and hydrogen, such as oxidation and reduction reactions, with specific examples for each. The paragraph further explores the similarities and differences between sodium (Na) and cobalt (Co) when added to water, highlighting their basic nature and the exothermic nature of their reactions.

15:04

🌡️ Reaction Dynamics and Storage of Oil

The fourth paragraph discusses endothermic reactions, which absorb heat from the surroundings, using the melting of ice and the dissolution of potassium nitrate in water as examples. It also explains combination reactions, balanced equations, and displacement reactions, providing examples for each. Additionally, it addresses the importance of particle size in reaction rates, using the example of shahabad tile reacting with HCL, and the proper storage of oil to prevent oxidation.

20:17

🛠️ Practical Chemistry: Reaction Observations

This paragraph focuses on the observation of chemical reactions, particularly the rusting process and the effects of particle size on reaction rates. It describes the formation of rust on iron through an electrochemical reaction and the impact of atmospheric components on metal oxidation. The paragraph also explains the importance of using airtight containers for storing oil to prevent oxidation and deterioration.

25:33

⚗️ Balancing Chemical Equations and Reaction Types

The final paragraph provides a stepwise guide to balancing chemical equations and identifies endothermic and exothermic reactions. It includes examples of both types of reactions and encourages students to observe and understand the processes involved. The paragraph concludes with a prompt for students to share a recommended educational channel, Wings of Fire Academy, with their peers.

Keywords

💡Chemical Reactions

Chemical reactions are processes where substances undergo a change to form new substances, involving the breaking and forming of chemical bonds. In the video, chemical reactions are the central theme, with various types such as oxidation, reduction, and displacement reactions being discussed. For example, the rusting of iron is an oxidation reaction where iron reacts with oxygen to form iron oxide.

💡Equations

Equations in the context of chemistry are symbolic representations of chemical reactions, showing the reactants and products along with their respective quantities. The video emphasizes the importance of balancing these equations to adhere to the law of conservation of mass. An example from the script is the formation of zinc sulfate and copper from copper sulfate and zinc.

💡Oxidation

Oxidation is a chemical process where a substance loses electrons or gains oxygen. The video explains oxidation in the context of rusting, where iron is oxidized to form iron oxide, and also in the conversion of ferrous sulfate to ferric sulfate, where the iron ion loses an electron.

💡Reduction

Reduction is the complementary process to oxidation, where a substance gains electrons or loses oxygen. The video describes reduction in the context of a redox reaction, where hydrogen sulfide is reduced while sulfur dioxide is oxidized, illustrating the simultaneous nature of these processes.

💡Displacement Reaction

A displacement reaction occurs when a more reactive element displaces a less reactive element in a compound, forming a new element and a new compound. The video script mentions this in the context of zinc displacing copper from copper sulfate to form zinc sulfate and elemental copper.

💡Electrolysis

Electrolysis is a process that uses an electric current to drive a non-spontaneous chemical reaction. The video describes the electrolysis of water as an example, where water is decomposed into hydrogen and oxygen gases through the application of electrical energy.

💡Double Displacement Reaction

Double displacement reactions involve the exchange of ions between two compounds to form two new compounds, often resulting in the formation of a precipitate. The script explains this with the reaction between zinc sulfate and barium chloride, forming barium sulfate as a precipitate and zinc chloride in solution.

💡Galvanization

Galvanization is a process used to protect iron or steel from rusting by coating it with a layer of zinc. The video script describes this process as a method to prevent the oxidation of iron sheets by applying a protective layer of zinc.

💡Catalyst

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. The video mentions manganese dioxide as a catalyst in the decomposition of hydrogen peroxide into water and oxygen, speeding up the reaction without being used up.

💡Reactants and Products

Reactants are the initial substances that participate in a chemical reaction, while products are the substances formed as a result of the reaction. The video script uses the combustion of coal as an example, where coal and oxygen are reactants, and carbon dioxide is the product.

💡Endothermic and Exothermic Reactions

Endothermic reactions absorb heat from their surroundings, while exothermic reactions release heat. The video distinguishes between the two, providing examples such as the dissolution of potassium nitrate being endothermic and the reaction of calcium oxide with water being exothermic.

Highlights

Introduction to solving questions from the lesson on chemical reactions and equations for class 10 science.

Explanation of oxidation and the process of galvanization to prevent rusting on iron sheets.

Understanding the oxidation reaction in the conversion of Ferris sulfate to feric sulfate.

Electrolysis of water explained as a decomposition reaction using electrical energy.

Double displacement reaction example with zinc sulfate and barium chloride forming a white precipitate.

Definition and example of a redox reaction where oxidation and reduction occur simultaneously.

Techniques to increase the rate of chemical reactions, such as using manganese dioxide as a catalyst in the decomposition of hydrogen peroxide.

Clarification of terms 'reactant' and 'product' with examples from chemical reactions.

Types of reactions with reference to oxygen and hydrogen, including oxidation and reduction reactions.

Similarities and differences between sodium (Na) and calcium (Ca) reactions with water, focusing on solubility and basicity.

Endothermic reactions are those that absorb heat from the surroundings, such as the melting of ice.

Combination reactions where multiple reactants form a single product, exemplified by the burning of magnesium.

Balanced chemical equations adhere to the law of conservation of mass, ensuring equal atom counts of elements.

Displacement reactions where a less reactive element is replaced by a more reactive one in a compound.

Observation of the rusting process and the chemical reaction involved in the formation of iron oxide.

The effect of particle size on the rate of chemical reactions, demonstrated with shahabad tile in HCL.

Safety precautions in handling concentrated sulfuric acid, including the correct method of dilution.

Importance of airtight containers for storing oil to prevent oxidation and maintain quality.

Identification of oxidation and reduction in given chemical reactions through the analysis of reactants.

Stepwise balancing of chemical equations to ensure stoichiometric accuracy.

Identification of endothermic and exothermic reactions based on heat exchange during chemical processes.

Matching of chemical terms with their descriptions in a table format for better understanding.

Transcripts

hello dear

students in today's video we will be

solving questions from the lesson on

chemical reactions and equations from

the class 10 science part one

textbook so let's start 10 science part

one chapter number three chemical

reactions and equations question and

answers

exercise question one choose the correct

option from the braet and explain the

statement giving

reason oxidation displacement

electrolysis reduction zinc copper

double displacement

decomposition sub question one to

prevent rusting a layer of zinc metal is

applied on iron

sheets

answer explanation due to moisture and

various components of atmosphere

oxidation of iron takes place a certain

type of reddish colored solid layer

collects on the iron

surface this layer is called rust its

chemical formula is iron 3 oxide

hydrated to avoid rusting a layer of

zinc metal is applied on iron sheets

which prevents iron sheets from directly

coming in contact with the atmosphere

and hence prevents

rusting this process of giving a thin

coating of zinc on iron to protect it

from rusting is called

galvanization sub question two the

conversion of Ferris sulfate to feric

sulfat is oxidation

reaction

answer explanation the conversion of

Ferris sulfate iron to sulfate into

feric sulfate iron 3 sulfate is an

oxidation

reaction in the above ionic reaction

when feric ion is formed from Ferris ion

the positive charge is increased by one

unit while this happens the ferris iion

loses one electron and losing of

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electrons is an oxidation

reaction sub question three when

electric current is passed through

acidulated water electrolysis of water

takes place

answer

explanation point one water decomposes

into hydrogen and oxygen gases on

passing electric current through

acidulated water point two this

decomposition takes place by means of

electrical

energy point three therefore it is

called as electris

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sub question four addition of an aquous

solution of zinc sulfate to an aquous

solution of berium chloride form a white

precipitate is an example of double

displacement

reaction

answer

explanation point one when aquous

solution of zinc sulfate is added to

aquous solution of berium chloride a

reaction takes place forming an aquous

solution of zinc chloride and a white

precipitate of barium

sulfate point two in this reaction ions

in the reactants are exchanged to form a

precipitate such reactions are called

double displacement

reactions question two WR answers to the

following sub question one what is the

reaction called when oxidation and

reduction take place

simultaneously explain with one

example

answer

point1 when oxidation and reduction take

place simultaneously in a given reaction

it is termed as reduxx

reaction point two during oxidation a

reactant combines with oxygen or loses

hydrogen and during reduction it gains

hydrogen or loses

oxygen point three is given directly

point 4 in the above reaction sulfur

dioxide is reduced and hydrogen sulfide

is

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oxidized sub question two how can the

rate of the chemical reaction namely

decomposition of hydrogen peroxide be

increased

answer point one the chemical reaction

in which two or more products are formed

from a single reactant is called a

decomposition

reaction hydrogen peroxide decomposes

into water and

oxygen point two the decomposition of

hydrogen peroxide into water and oxygen

takes place slowly at room

temperature however the rate of this

chemical reaction can be increased by

adding manganese dioxide powder to it

here manganese dioxide acts as a

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Catalyst sub question

three explain the term reactant and

product giving

examples

answer point one a chemical reaction is

a process in which some substances

undergo bond breaking and are

transformed into new substances by the

formation of new

bonds point two the sub substances

taking part in a chemical reaction are

called reactants whereas the substances

formed as a result of a chemical

reaction by the formation of new bonds

are called

products point three for

example point a formation of carbon

dioxide gas by combustion of coal and

air is a chemical

reaction in this reaction coal carbon

and oxygen from Air are the reactants

while carbon dioxide side is the

product Point p is given

directly in the above equation copper

sulfate and zinc are the reactants and

zinc sulfate and copper other

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products sub question 4 explain the

types of reaction with reference to

oxygen and hydrogen

illustrate with

examples

answer point one types of reactions with

reference to oxygen and hydrogen are

oxidation reactions and reduction

reactions oxidation

reaction the chemical reaction in which

a reactant combines with oxygen or loses

hydrogen to form the product is called

an oxidation

reaction for

example one mag magnesium reacts with

oxygen to form magnesium oxide to

magnesium plus oxygen yields to

magnesium

oxide here oxygen combines with

magnesium to form magnesium oxide two

magnesium hydride loses hydrogen to form

magnesium and hydrogen

gas magnesium hydride yields magnesium

plus

hydrogen here magnesium hydride loses

hydrogen

reduction

reaction the chemical reaction in which

a reactant combines with hydrogen or

loses oxygen to form a product is called

a reduction

reaction for

example carbon plus 2 hydrogen yields

methane here carbon combines with

hydrogen and forms the compound methane

mercuric oxide yields Mercury plus

oxygen

yeah mercuric oxide loses oxygen to form

Mercury sub question

five explain the similarity and

difference in two events namely adding

na to water and adding Co to water

answer

similarity point one both Na and Co

dissolve in water

now it dissolves in water forming aquous

sodium hydroxide while Co reacts with

water to form calcium

hydroxide point two both are bitter in

taste and turn red litmus paper blue in

other words both are basic in nature

both are exothermic

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reactions point three a after adding

water the properties of aquous solutions

of sodium hydroxide and calcium

hydroxide are

different

difference

point1 sodium hydroxide is highly

soluble in water whereas calcium oxide

is less soluble in water point two

aquous solution of sodium hydroxide is

monovalent whereas aquous solution of

calcium hydroxide is divalent

Point 3 as sodium hydroxide is highly

soluble in water it forms a strong base

whereas calcium hydroxide is a weak

base question

three explain the following terms with

examples sub question one endothermic

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reaction answer point one a reaction in

which heat is either absorbed from the

surrounding or has to be supplied

continuously from outside is called as

endothermic

reaction point two for example melting

of ice dissolution of potassium nitrate

in water during the process of

dissolution of potassium nitrate in

water heat from the surroundings is

absorbed and therefore the temperature

of the resulting solution is less point

three the process in which heat is

absorbed from outside is called

endothermic

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process sub question two combination

reaction

answer point one when two or more

reactants combine in a reaction to form

a single product it is called a

combination

reaction point

for example when a magnesium strip is

burnt in air it combines with oxygen to

form white ash of magnesium

oxide 3 is given

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directly sub question

three balanced

equation

answer

point1 the number of atoms of the

elements in the react is same as the

number of atoms of those elements in the

products such an equation is called

balanced

equation point two in any reaction the

total mass of each of the respective

elements in the reactants is same as the

total mass of each of the respective

elements in the

products point three this is an

accordance with the law of conservation

of mass point four is given directly

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sub question four displacement

reaction

answer1 the reaction in which the place

of the ion of a less reactive element in

a compound is taken by another more

reactive element by formation of its own

ions is called displacement

reaction Point 2 is given

directly Point 3 in the above equation

when zinc dust is added to blue colored

copper sulfate solution a colorless

solution of zinc sulfate is formed and

copper is deposited on

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zinc point four the zinc ions formed

from zinc atoms take the place of copper

ions in copper sulfate and copper atoms

formed from copper ions come out it

means that zinc displaces Copper from

copper

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sulfate question

four explain the following terms with

examples sub question one when the gas

forms on heating limestone is passed

through freshly prepared lime water the

lime water turns

milky

answer point one on heating Limestone

undergo thermal decomposition to form

calcium oxide quick lime and carbon

dioxide point two calcium oxide when

dissolved in water forms calcium

hydroxide lime water

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point three when carbon dioxide is

passed through lime water it turns milky

due to formation of white precipitate of

calcium

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carbonate sub question two it takes time

for pieces of shahabad tile to disappear

in HCL but its powder disappears

rapidly answer

point one when HCL is added to shahabad

Stone effervescence of carbon dioxide is

formed point two the carbon dioxide

effervescence is formed slowly with the

pieces of shahabad tiles while at a

faster speed with a powder point three

this is because the rate of a reaction

depends upon the size of the particles

of the reactants taking part in the

reaction point four

the smaller the size of the reactant

particles the more is the surface area

available for the reaction and higher is

the rate of

reaction

five hence it takes time for pieces of

shahabad tiles to disappear in HCL but

its powder disappears

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rapidly sub question three while

preparing dilute sulfuric acid from

concentrated sulfuric acid in the

laboratory the concentrated sulfuric

acid is added slowly to water with

constant

stirring

answer1 concentrated sulfuric acid is a

hazardous highly corrosive

chemical it has a higher density than

water and is hygroscopic which means

that it absorbs water from the air point

two in the process of d solution of

concentrated sulfuric acid with water a

very large amount of heat is

liberated Point 3 as a result water gets

evaporated instantaneously along with

splashing of acid which may cause an

accident point four to avoid this the

required amount of water is taken in a

glass container and a small quantity of

concentrated sulfuric acid at a time is

added with stirring

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point five therefore only a small amount

of heat is liberated at a time sub

question four it is recommended to use

airtight container for storing oil for

long time

answer

point1 air heat and light affect the

quality of edible oil which deteriorates

through oxidation Rancid

point two the oxidation process is

greatly enhanced when edible oils are

stored in containers that are not

airtight and in areas where oil is

exposed to air heat and light point

three hence it is recommended to use

airtight containers for storing oil for

long time to prevent it from getting

oxidized

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question

five observe the following picture or

write down the chemical reaction with

explanation answer is on the next

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slide

answer point one in the above diagram

the process of rusting takes plays point

two a certain type of reddish colored

solid layer cols on the metallic

surface point three this layer is called

rust point 4 its chemical formula is

iron 3 oxide X water the rust is formed

by an electrochemical

reaction point

five different regions on the surface of

iron become anode and

cathode point 6 iron is oxidized to iron

2 plus in the anode region

7 8 and 9 is on the next

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slide point 10 due to various components

of atmosphere oxidation of metal state

takes place consequently resulting in

their

damage Point

11 this is called corrosion iron rusts

and a reddish colored layer is collected

on it this is corrosion of

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iron question

six identify from the following

reactions the reactants that undergo

oxidation and

reduction answer is given

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directly question

7 balance the following equation

stepwise answer is given directly

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question

8 identify the endothermic and

exothermic

reactions sub question one hydrochloric

acid plus sodium hydroxide yields sodium

chloride plus water plus heat

answer exothermic

reaction sub question two to Potassium

chlorates solid yield to potassium

chloride solid plus three oxygen

gases answer endothermic

reaction sub question three calcium

oxide plus water yields calcium

hydroxide plus heat

answer exothermic

reaction sub question four calcium

carbonate solid yields calcium oxide

solid plus carbon dioxide gas

answer endothermic re

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action question n match the column in

the following

table answer is given

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directly great

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friends subscribe to it but what's the

Channel's name Wings of Fire Academy

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