Language of Chemistry Exe-1A Chemistry Class-9 ICSE Selina Publishers

Language of Chemistry Exe-1A Chemistry Class-9 ICSE Selina Publishers Solutions Chapter-1. Step By Step ICSE Selina Concise Solutions of Chapter-1 Language of Chemistry with All Exercise including MCQs, Very Short Answer Type, Short Answer Type, Long Answer Type, Numerical and Structured/Application Questions Solved . Visit official Website CISCE for detail information about ICSE Board Class-9.

Language of Chemistry Exe-1A Chemistry Class-9 ICSE Concise Selina Publishers

Board	ICSE
Publications	Selina Publication
Subject	Chemistry
Class	9th
Chapter-1	Language of Chemistry
Book Name	Concise
Topics	Solution of Exercise – 1A
Academic Session	2023-2024

A. Exercise – 1A

Language of Chemistry Class-9 Chemistry Concise Solutions  

Page 10

Question 1.
Complete the following statements by selecting the correct option :

(a) The formula of a compound represents

(i) an atom

(ii) a particle

(iii). a molecule

(iv) a combination

(b) The correct formula of aluminum oxide is

(i) AlO3

(ii) AlO2

(iii) . Al2O3

(iv) Al3o2

(c) The valence of nitrogen in nitrogen dioxide (NO2) is

(i) .one

(ii) two

(iii) .three

(iv) four

Answer:

(a)iii. The formula of a compound represents a molecule.

(b)iii. The correct formula of aluminum oxide is Al2O3.

(c)iv. The valence of nitrogen in nitrogen dioxide (NO2) is four.

Question 2.

Match the following:

………………

Answer:

Answer:

Compound	Formula (Ans)
(a) Boric acid	xvi. H3BO3
(b) Phosphoric acid	xvii. H3PO4
(c) Nitrous acid	xv. HNO2
(d) Nitric acid	xiv. HNO3
(e) Sulphurous acid	xiii. H2SO3
(f) Sulphuric acid	xviii. H2SO4
(g)  Hydrochloric acid	xii. HCl
(h) Silica (sand)	ii. SiO2
(i) Caustic soda (sodium hydroxide)	i. NaOH
(j) Caustic potash (potassium hydroxide)	iv. KOH
(k) Washing soda (sodium carbonate)	iii. Na2CO3
(l) Baking soda (sodium bicarbonate)	vi. NaHCO3
(m) Lime stone (calcium carbonate)	v. CaCO3
(n) Water	viii. H2O
(o) Hydrogen sulphide	vii. H2S
(p) Ammonia	xi. NH3
(q) Phosphine	ix. PH3
(r) Methane	x. CH4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Question 3.

Select the basic and acidic radicals in the following compounds.

(a)MgSO₄

(b)(NH₄)₂SO₄

(c)Al₂ (SO₄)₃

(d)ZnCO₃

(e)Mg (OH) ₂

Answer :

	Acidic radical	Basic radical
a. MgSO4	SO4–	Mg+
b.     (NH4)2SO4	SO4–	NH4+
c.     Al2(SO4)3	SO4–	Al3+
d. ZnCO3	CO3–	Zn2+
e.     Mg(OH)2	OH–	Mg2+

 

 

 

 

 

 

Question 4.

Give the formula and valence of:

(a) Acuminate ……

(b) Chromate ………

(c) Aluminum ……

(d) Cupric ……

Answer:

	Name	Formula	Valency
a.	Aluminates	AlO2	-2
b.	Chromate	CrO4	-2
c.	Aluminum	Al	+3
d.	Cupric	Cu	+2

 

 

 

 

 

Question 5.

What do the following symbols stand for?

(a) H   (b)   H₂   (c) 2H     (d) 2H₂

Answer:

(a) One Hydrogen atom

(b) Hydrogen molecules

(c) Two Atom of hydrogen

(d) Two molecules of hydrogen.

Question 6.

Write the chemical names of the following compounds:

(a) Ca₃ (PO₄)₂

(b) K₂CO₃

(c)K₂MnO₄

(d) Mn₃ (BO₃)₂

(e) Mg (HCO₃)₂

(f) Na₄Fe (CN)₆

(g) Ba (ClO₃)₂

(h) Ag₂SO₃

(i) (CH₃COO) _2Pb

(j) Na₂SiO₃

Answer:

Chemical names of compounds:

Ca₃(PO₄)₂– Calcium phosphate

K₂CO₃– Potassium carbonate

K₂MnO₄ – Potassium manganite

Mn₃(BO₃)₂– Manganese (II) borate

Mg(HCO₃)₂– Magnesium hydrogen carbonate

Na₄Fe(CN)₆– Sodium Ferro cyanide

Ba(ClO₃)₂– Barium chlorate

Ag₂SO₃– Silver sulphite

(CH₃COO)₂Pb – Lead acetate

Na₂SiO₃– Sodium silicate

Question 7.

Write chemical formula of the sulphate of Aluminum, Ammonium and Zinc.

Answer:

Valences of aluminum, ammonium and zinc are 3, 1 and 2, respectively.

The valences of sulphate is 2.

Hence, chemical formulae of the sulphates of aluminum, ammonium and zinc are Al₂(SO₄)₃, (NH₄)₂SO₄ and ZnSO₄.

Question 8.

The valence of an element Ais 3 and that of element Bis 2. Write the formula of the compound formed by the combination of Aand B.

Answer:

Formula of the compound = A₂B₃

Question 9.

Give the names of the following compounds.

(a) KCLO

(b) KCLO₂

(c) KCLO₃

(d) KCLO₄

Answer:

(a)Potassium hypochlorite

(b)Potassium chlorate

(c)Sodium chlorate

(d)Sodium perchlorate

Question 10.

The formula of the sulphate of an element M is M₂ (SO₄)₃Write the formula of its Chloride Oxide Phosphate Acetate

Answer:

The valence of metal M is 3. So, the formulae are as follows:Chloride – MCl₃Oxide – M₂O₃Phosphate – M(PO₄)Acetate – M(CH₃COO)₃

Question 11.

What is a symbol of an element ? What information does it convey?

Answer:

A symbol is the short form which stands for the atom of a specific element or the abbreviations used for the names of elements

It represents a specific element.

(i)It represents one atom of an element.

(ii)A symbol represents how many atoms are present in its one gram (gm) atom.

(iii) It represents the number of times an atom is heavier than one atomic mass unit (amu) taken as a standard.

Question 12.

Why is the symbol S for Sulphur, but Na for sodium and Si for silicon?

Answer:

In most cases, the first letter of the name of the element is taken as the symbol for that element and written in capitals (e.g. for Sulphur, we use the symbol S). In cases where the first letter has already been adopted, we use a symbol derived from the Latin name (e.g. for sodium/Atrium, we use the symbol Na). In some cases, we use the initial letter in capital together with a small letter from its name (e.g. for silicon, we use the symbol Si).

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A. Exercise – 1A

Language of Chemistry Class-9 Chemistry Concise Solutions  

Page 11

Question 13.

Write the full form of IUPAC. Name the elements represented by the following symbols:

Au, Pb, Sn, Hg

Answer:

The full form of IUPAC is International Union of Pure and Applied Chemistry.

Names of the elements:

Au – Gold

Pb – Lead

Sn – Tin

Hg – Mercury

Question 14.

If the symbol for Cobalt, Co, were written as CO, what would be wrong with it?

Answer:

Co stands for Cobalt. If we write CO, then it would mean that it is a compound containing two non-metal ions, i.e. carbon and oxygen, which forms carbon monoxide gas.

Question 15.

What is meant by atomicity? Name the diatomic element.f

Answer:

The number of atoms of an element that join together to form a molecule of that element is known as its automatically.

Diatomic molecules: H₂, O₂, N₂, Cl₂

Question 16.

(a) Explain the terms ‘valence’ and ‘variable valency

(b) How are the elements with variable valence named? Explain with an example

Answer:

(a)

Valence of Na is +1 because it can lose one electron.

Valence of O is -2 because it can accept two electrons.

Variable valence: It is the combining capacity of an element in which the metal loses more electrons from a shell next to a valence shell in addition to electrons of the valence shell.

(b)

If an element exhibits two different positive valences, then

for the lower valence, use the suffix -OUS at the end of the name of the metal

for the higher valency, use the suffix -IC at the end of the name of the metal.

Example:

Element	Lower valence	Higher valency
Ferrum (Iron)	Ferrous (Fe2+)	Ferric (Fe3+)

 

 

 

 

Question 17.

a) What are chemical formulas?

(b) What is the significance of formula? Give an example to illustrated.

Answer:

(a) a set of chemical symbols showing the elements present in a compound and their relative properties.

(b) Significance of the molecular formula:

It represents both molecule and molecular mass of the compound. represents the respective number of different atoms present in one molecule of the compound.and Also It represents the ratios of the respective masses of the elements present in the compound.

Question 18.

What do you understand by the following terms?

(a) Acid radical    (b) Basic radical

Answer :

(a) Acid radical:

The electronegative or negatively charged radical is called an acid radical.

Examples:Cl^–, O^2-

(b) Basic radical:

The electropositive or positively charged radical is called a basic radical.

Examples:K⁺, Na⁺

Question 19.

Write the basic radicals and acidic radicals of the following and then write the chemical formulae of these compounds.

(a)Barium sulphate

(b)Bismuth nitrate

(c) Calcium bromide

(d) Ferrous sulphide

(e) Chromium sulphate

(f) Calcium silicate

(g) Stannic oxide

(h) Sodium zincate

(i) Magnesium phosphate

(j) Sodium thiosulphate

(k) Stannic phosphate

(l) Nickel bisulphate

(m) Potassium manganite

(n) Potassium Ferro cyanide

Answer:

S. No.	Compound	Basic radical	Acidic radical	Formula
a	Barium sulphate	Ba2+	SO42-	BaSO4
b	Bismuth nitrate	Bi3+	NO3–	Bi(NO3)3
c	Calcium bromide	Ca2+	Br–	CaBr2
d	Ferrous sulphide	Fe2+	S2-	FeS
e	Chromium sulphate	Cr3+	SO42-	Cr2(SO4)3
f	Calcium silicate	Ca2+	SiO32-	CaSiO3
g	Stannic oxide	Sn4+	O2-	SnO2
h	Sodium zincate	Na1+	ZnO22-	Na2ZnO2
i	Magnesium phosphate	Mg2+	PO43-	Mg3(PO4)2
j	Sodium thiosulphate	Na1+	S2O32-	Na2S2O3
k	Stannic phosphate	Sn4+	PO43-	Sn3(PO4)4
l	Nickel bisulphate	Ni2+	HSO4–	Ni(HSO4)2
m	Potassium manganate	K1+	MnO42-	K2MnO4
n	Potassium ferrocyanide	K1+	Fe(CN)64-	K4[Fe(CN)6]

Question 20.

Give the names of the elements and number of atoms of those elements present in the following compounds.

(a) Sodium sulphate

(b) Quick lime

(c) Baking soda

(d) Ammonia

(e) Ammonium dichromate

Answer:

(a) Sodium sulphate
Formula: Na₂SO₄
∴ It contains 2 atoms of Sodium (Na), 1 atom of Sulphur (S) and 4 atoms of Oxygen (O).(b) Quick lime
Formula: CaO
∴ It contains 1 atom of Calcium (Ca) and 1 atom of Oxygen (O).

(c) Baking soda
Formula: NaHCO₃
∴ It contains 1 atom of Sodium (Na), 1 atom of Hydrogen (H), 1 atom of Carbon (C) and 3 atoms of Oxygen (O).

(d) Ammonia
Formula: NH₃
∴ It contains 1 atom of Nitrogen (N) and 3 atoms of Hydrogen (H).

(e) Ammonium dichromate
Formula: (NH₄)₂Cr₂O₇
∴ It contains 2 atoms of Nitrogen (N), 8 atoms of Hydrogen (H), 2 atoms of Chromium (Cr) and 7 atoms of Oxygen (O).

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