Class-7 Dalal Simplified Language of Chemistry ICSE Solutions

Class-7 Dalal Simplified Language of Chemistry ICSE Solutions Chapter-5. Step by step solutions of New Simplified Dr Viraf J Dalal Middle School Chemistry Allied Publishers for ICSE Class-7 with MCQ , Practice Problems, Exercise, Objective Type Questions and Fill in the Blanks.. Visit official Website CISCE for detail information about ICSE Board Class-7.

Class-7 Dalal Simplified Language of Chemistry ICSE Solutions Chapter-5


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Chemical Equations

Exercise

Objective Type Questions


EXERCISE-5 Chemical Equations

Class-7 Dalal Simplified Language of Chemistry ICSE Solutions Chapter-5

Question 1.

Write the word equation for the following molecular equations:

CuCo3→ CuO + C02 [g] State the characteristics or indications occurring in the above reaction.
Answer 1:
Copper carbonate → Copper oxide + carbon dioxide
Copper carbonate is green coloured, it changes to black when it turns into copper oxide.

Question 2.
ICSE Solutions for Class 6 History and Civics - Language History-300
State which characteristic does [g] in the above reaction indicate.
The word equation of
Answer 2:
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Carbon dioxide evolved

Question 3.
ICSE Solutions for Class 6 History and Civics - Language History-2

State which characteristic is observed in the above reaction.

Give an example of a similar above characteristic, seen between two other gaseous reactants.

Answer 3:

Ammonia + Hydrogen Chloride ⥬ Ammonium Chloride

The state of matter of reactants changes from gaseous to solid in this reaction.

Other examples:

  1. 2H2 (g) + O2 (g) → 2H2O (l)
  2. C (s) + 2S (s) → CS2 (l)

Question 4.
Write word equation for the following molecular equations:

Na2SO3 + 2HCl [dil.] → 2NaCl + H2O + S02 [g]
Answer 4:
Sodium carbonate + hydrochloric acid → Sodium chloride + water + carbon dioxide

Question 5.
Write word equation for the following molecular equations:

FeSO4 + 2NaOH Na2SO4 + Fe(OH)2 ↓

State why [↓] indication is seen after Fe(OH)2 and not after Na2SO4
Answer 5:
Iron (II) Sulphate + Sodium hydroxide → Sodium sulphate + Iron (II) hydroxide ↓
The precipitate formed is shown with ↓ in a chemical reaction. Hence, Fe(OH)2 is the precipitate formed but not Na2SO4.

Question 6.
ICSE Solutions for Class 6 History and Civics - Language History-400
State why [+ Δ] indication is seen after NH3. State what 200 atmospheres – indicates.State the function of Fe in the above reaction.
Answer 6:
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  1. + Δ at the end of the reaction represents heat evolved.
  2. NH4 decomposes in the pressure of 200 atmosphere
  3. Fe act as catalyst in the reaction.

Question 7.
ICSE Solutions for Class 6 History and Civics - Language History-7

State which form of energy is utilised in the above chemical reaction.
Answer 7:
Hydrogen + Chlorine →Hydrogen Chloride
In diffused sunlight gives HCl gas

Question 8.
AgN03 + HCI → HNO3 + AgCl ↓
State whether AgCl is soluble or insoluble in HN03.
Answer 8:
Silver nitrate + dil. hydrochloric acid → Nitric acid + Silver chloride
AgCl insoluble in HNO3

Question 9.
CaO + H2 Ca (OH)2 + Δ
State why [+ Δ ] is not written in the reaction, if ZnO reacts with H2O.
Answer 9:
Calcium oxide + Water→Calcium hydroxide + heat
When ZnO reacts with H20, then equation is
ZnO + H20 →Zn(OH)2
Heat is not evolved hence + Δ is not written in the reaction

Question 10.
CuS04 + 2NaOHNa2S04 + Cu(OH)2↓
State the colour of the products.
Answer 10:
Copper (II) Sulphate + Sodium hydroxide→ Sodium sulphate + Copper (III) hydroxide.
The colour of Cu(OH)2↓ is pale blue.


EXERCISE-5 (Part-2)

Class-7 Dalal Simplified Language of Chemistry ICSE Solutions Chapter-5

Question 1.
Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.
Answer 1:
A reaction between matter that react together and form new products.

The  substances that undergo  reaction are reactants while the new substances formed are called products.

Question 2.
Represent the addition of dilute sulphuric acid to zinc by means of a chemical equation. State the function of the arrow between the reactants and products.
Answer 2:

  • Reactants

Left hand side write the reactants (substances which take part in a reaction).

  • Products

Right hand side write the products (substances formed as a result of the reaction).

Chemical equation formed is

Zn [dil.] + H2SO4 ZnSO4 +H2[g]

The function of the arrow (→) between the reactants and products is that it represents the chemical reaction taken place between two reactants.

Question 3.

A chemical reaction is generally accompanied by certain external indications or characteristics. These include – change of – (a) colour

(b) state

(c) smell

(d) evolution of gas 

(e) formation of precipitate

(f) evolution or absorption of heat.

With reference to change of colour – state the change in colour seen when the following arc.heated – (1) copper carbonate (2) zinc carbonate (3) mercury [II]oxide (4) lead [IV] oxide.

Answer 3:
Change of colour — In certain chemical reactions a change of colour is seen to be observed. Heat on substances to observe change in colour of reactants and products.

on heating product formed

  1.  CuCO3 → CuO + CO2[g]
  2.  ZnCO3 → ZnO + CO2 [g]
  3.  2HgO → 2Hg + O2 [g]
  4. 2PbO2→2PbO + O2 [g]

 change in colour

  1. Copper carbonate is green coloured, when heated it gives out a black solid copper oxide.
  2. Zinc carbonate is white coloured, when heated it gives a yellow solid – zinc oxide
  3. Mercury [II] oxide is red, when heated it turns silvery
  4. Lead [IV] oxide is brown, when heated it turns yellow.

Question 4.
Give a balanced equation for addition of iron to copper [II] sulphate solution. State the change in colour seen.
Answer 4:
ICSE Solutions for Class 6 History and Civics - Language History-8
colour change from blue to light green

Question 5.
In certain reactions a change of state is observed i.e. solid to liquid, liquid to gas etc. – State the change of state of the products – to give the respective reactants in each case.
Answer 5:
(a)
Carbon with sulphur
ICSE Solutions for Class 6 History and Civics - Language History-11
(b)

ICSE Solutions for Class 6 History and Civics - Language History-12
(c)

2H2[ g] + O2[g] + 2H2O[l]

(d)

ICSE Solutions for Class 6 History and Civics - Language History-13
Change is shown as S for solid and l for liquid while g for gas

Question 6.                      
In certain reactions a change of smell is observed. Give two examples from daily life of the same.
Answer 6:

reactions where change of smell

  1. Spoiling of milk
  2. rotten of eggs produce foul smell

Question 7.
In certain reactions an insoluble solid called precipitate is formed. State the colour and name of the precipitate formed in each of the following reactions involving addition of:
(a) Dilute hydrochloric acid to silver nitrate.
(b) Iron [II] sulphate to sodium hydroxide.
(c) Iron [III] chloride to ammonium hydroxide.
(d) Copper [II] sulphate to sodium hydroxide.
(e) Lead nitrate to ammonium hydroxide.?
Answer 7:
(a)
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The precipitate Silver Chloride is milky

(b)
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The precipitate  Iron [II] hydroxide dirty green

(c)
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The precipitate  Iron [III] hydroxide reddish brown

(d)
ICSE Solutions for Class 6 History and Civics - Language History-17
The precipitate Copper [II] hydroxide pale blue

(e)
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The precipitate Lead hydroxide chalky white

Question 8.
Give examples of exothermic reactions i.e. heat evolved in each of the following:
(a) reaction between a solid and a liquid
(b) reaction between two gases
Give two examples of exothermic reactions seen in everyday life.
Answer 8:
(a)
CaO + H2Ca(OH)3 + Δ

(b)
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Some Examples which are exothermic in nature

  1. CaCO3 with water for whitewash– .
  2. burning of fuel –
  3.  Body of mammals and birds – .

Question 9.          
Give one example in each case where supplying energy [given below] is necessary for a chemical reaction.
(a) Heat energy
(b) Light energy
(c) Electrical energy
(d) Pressure
(e) Catalyst
Answer 9:
(a)
ICSE Solutions for Class 6 History and Civics - Language History-20
(b)
ICSE Solutions for Class 6 History and Civics - Language History-21
(c)
ICSE Solutions for Class 6 History and Civics - Language History-22
(d)

ICSE Solutions for Class 6 History and Civics - Language History-23
(e)
ICSE Solutions for Class 6 History and Civics - Language History-24

Question 10.              
Representation of the results of a chemical change – is a chemical equation.
For the equation: FeCl3 + 3NH4OH 3NH4Cl + Fe(OH)3 ↓
Answer the following:
(a) Write the word equation for the above molecular equation.
(b) Is the equation given above a balanced equation. Give reasons.
(c) Name the reactants and the products in the above equation.
(d) What is the indications of the arrow between the reactants and the products and of the arrow pointing downwards at the end.
Answer 10:
(a)
Iron (III) chloride + ammonium hydroxide → Ammonium chloride + Iron (III) hydroxide
(b)
Yes, because in this reaction the total number of atoms of each elements in the reactants, on the left side of the equation is equal to the number of products formed on the right side of the equation.
(c)

Reactants – Iron (III) Chloride and Ammonium hydroxide, products – Ammonium Chloride and Iron (III) Hydroxide

(d)

The arrow between reactants and products indicates the chemical reaction taking place between reactants. The arrow pointing downwards indicates formation of precipitate.

Question 11.

Give word equations for the following chemical reactions and give the names of the products formed.
(a) Zn + 2HC1→ ZnCl2 + H2
(b) CuO + H2SO4→CuS04 + H2O
(c) Zn + S → ZnS
(d) ZnCO3 → ZnO + CO2
(e) NH3 + HCl→ NH4Cl
Answer 11:
(a)
Zinc + dilute Hydrochloric acid→ Zinc chloride + Hydrogen
(b)
Copper + Sulphuric Acid → Copper(II)sulphate + water 
(c)
Zinc + Sulphur → Zinc Sulphide
(d)
Zinc carbonate →Zinc oxide + Carbon dioxide
(e)
Ammonia + Hydrogen chloride → Ammonium chloride 

(Product formed are highlight in reaction)


Objective Type Questions

Language of Chemistry Class-7 Dalal ICSE New Simplified Dr Viraf J Dalal Middle School Allied Publishers Solutions. Chapter-5

Question-1

Select the correct answer for the following options:

A: Hydrogen B: Copper [II] oxide C: Oxygen D: Copper [II] hydroxide E: Ammonia

  1. The black residue obtained on heating copper carbonate.
    The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.
  2. The gas obtained when potassium chlorate is heated in the presence of a catalyst.
  3. The pale blue precipitated obtained when copper [II] sulphate reacts with sodium hydroxide.
  4. The gas which reacts with oxygen to give a neutral liquid.
  5. The gas which reacts with oxygen to give a neutral liquid.

Answer-1

  1. B: Copper [II] oxide
  2. A: Hydrogen
  3. C: Oxygen
  4. D: Copper [II] hydroxide
  5. E: Ammonia

Question-2. 

Give a word equation for each of the following reactions.

Question 1.
Two solids which combine on heating, to give a liquid.
Answer:
Carbon + Sulphur → Carbon disulphide
C + S → CS(l)

Question 2.                        Class-7 Dalal Simplified Language

  1. Two solids which combine on heating, to give a liquid.
  2. Two gasses which combine to give a solid
  3. A compound which on heating shows – colour change from brown to yellow
  4. A salt which reacts with aluminium hydroxide to give a reddish-brown precipitate.
  5. An exothermic reaction where both the reactants are gases, one of which is oxygen

Answer-2

  1. Carbon + Sulphur → Carbon disulphide
  2. Ammonia + Hydrogen chloride → Ammonium chloride
  3. Lead dioxide → lead oxide + oxygen
  4. Iron (II) chloride + ammonium hydroxide → ammonium chloride + iron (III) hydroxide
  5. Hydrogen + Oxygen → water

Question-3. 

Name the following:

  1. The silvery residue obtained on heating mercury oxide.
  2. The gas evolved when dilute acid is added to chalk (limestone)
  3. Two non-metal which react explosively when brought in close contact.
  4. Two gases which react under pressure in presence of a catalyst at elevated temperatures to give a gaseous product.
  5. A catalyst which increases the rate of a chemical reaction.

Answer-3

  1. Mercury
  2. Carbon dioxide
  3. Iodine phosphorus
  4. Nitrogen and hydrogen
  5. Manganese dioxide

Question-4.

Give reasons for the following:

  1. Even though rusting is an exothermic reaction, the heat evolved when an iron nail rusts are unnoticeable.
  2. Electrolytic decomposition of water is a reaction involving a change of state.
  3. A characteristic change of colour is seen when a piece of iron is added to copper sulphate solution.
  4. The catalytic oxidation of sulphur dioxide to sulphur trioxide is represented by a double arrow between reactants and products, formed in the chemical reaction.

Answer-4

  1. Rusting of iron is a slow reaction and the heat evolved is very less, which is unnoticeable.
  2. Electrolytic decomposition of water is due to the passage of electric current through it.
  3. When iron is added to copper [II] sulphate solution, iron displaces copper from copper sulphate and forms ferrous sulphate which is pale green coloured and there is a reddish-brown deposit on copper.
  4. The double arrow indicates that the reaction is reversible.
  5. Silver nitrate is deposited in coloured bottles because it gets decomposed by sunlight.

Question 5.
Write word equations for the following chemical reactions given below. Also state the observation seen in each case.

  1. …………
  2. …………..
  3. ……….
  4. ………..
  5. …………

Answer-5:

  1. Zinc carbonate → zinc oxide + carbon dioxide Carbon dioxide gas is formed in this reaction.
  2. Sodium Chloride + Silver nitrate → Silver chloride + Sodium nitrate A white precipitate (silver chloride) is formed in the above chemical reaction.
  3. Sodium sulphite + hydrochloric acid → sodium chloride + water + sulphur dioxide Sulphur dioxide gas is formed in this reaction.
  4. Sulphur dioxide + oxygen ⇌ Sulphur trioxide
  5. Lead nitrate + ammonium hydroxide → ammonium nitrate + lead hydroxide Lead hydroxide is a chalky white precipitate formed in this reaction.

 

End of Language of chemistry dalal simplified chemistry class-7 Solution

 

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