Class-6 Dalal Elements Compounds and Mixtures ICSE Chemistry
Class-6 Dalal Elements Compounds and Mixtures ICSE Chemistry New Simplified Solutions Dr Viraf J Dalal Middle School Allied Publishers Solutions. Chapter-2. We Provide Step by Step Solutions of Exercise/Lesson -2 Elements Compound and Mixtures with Objective Type Questions, Fill in the blanks and Give reason , Match the following of Dr Viraf J Dalal Middle School Chemistry Allied Publishers. Visit official Website CISCE for detail information about ICSE Board Class-6.
Class-6 Dalal Elements Compounds and Mixtures ICSE Chemistry New Simplified Solutions Chapter-2
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Exercise- Elements & Compounds
Class-6 Dalal New Simplified ICSE Chemistry Solutions Chapter-2
Classify substances into pure and impure substances in the form of a chart or tabulation.
Differentiate between the terms – elements, compounds & mixtures.
Element is the basic unit of matter, which cannot be broken down into more simpler substances by any way but can be combined to form new substances.It is a pure substance and classified into metals, non-metals, metalloids and noble gases.
Example – Sulphur, Gold , Iron, Hydrogen, Carbon, Oxygen
Compounds – combination of two or more elements in fix ratio Through chemical reactions are called Compound. with new properties other than components Example – Glucose, Oil, Water,
Mixtures – a combination of two or more elements in any ratio with same properties as components
Example – Sugar Syrup, Salty Water, Air, Chalk powder, Washing Soda
The important physical properties of substances are colour, odour, nature, density & solubility in water. Name –
(a) two coloured gases (with their colours)
(b) a gas with a pungent, choking odour which is lighter than air
(c) a poisonous gas almost as heavy as air.
- Chlorine – greenish yellow
- Nitrogen dioxide – reddish brown.
(c) Carbon monoxide
Complete the statement – an element is a pure substance made up of (identical/different) atoms.
An element is a pure substance made up of identical atoms.
Draw a labelled diagram of an atom including its nucleus, orbits & their contents.
Elements are classified into – Metals – Non-metals – Metalloids – Noble gases. State which of A, B, C, D is a –
- Metallic element
- Non-metallic element
- Noble gas.
A : Is non-malleable, non-ductile & a poor conductor of electricity____
B : Has lustre, is malleable and ductile & a good conductor of heat ____
C : Is unreactive and inert and present in traces in air____
D : Shows properties of both metals and non-metals____
A: Non metallic element
B: Metallic element
C: Noble gas
An atom of an element is denoted by a ‘symbol’. Explain the meaning of the term “symbol” State a reason for representing the following elements by their symbols.
(a) Hydrogen by ‘H’
(b) Helium by ‘He’
(c) Copper by ‘Cu’
Symbols : The short form or abbreviated name of the element (or radicals)
The reason for representing the following elements by their symbols are as follow :
(a) Hydrogen by ‘H’ – First letter of the name of element
(b) Helium by He – First two letters of the name of Noble gases.
(c) Copper by ‘Cu’ – Deriving symbols from their Latin names
Match the metallic elements – with their correct symbols Metallic
(a) Potassium (b) Sodium (c) Calcium (d) Magnesium (e) Zinc (f) Aluminium (g) Iron (h) Lead (i) Copper (j) Mercury (k) Silver (l) Platinum (m) Gold
Symbols – (1) Ca (2) Zn (3) Pb (4) Hg (5) Cu (6) Au (7) K (8) Fe (9) Al (10) Na (11) Mg (12) Pt (13) Ag
Match the non-metallic elements – with their correct symbols
Non- Metallic elements –
(a) Carbon (b) Chlorine (c) Oxygen (d) Phosphorus (e) Hydrogen (f) Nitrogen (g) Iodine (h) Bromine (i)Fluorine (j) Silicon (k) Sulphur
Symbols – (1) O (2) I (3) Si (4) C (5) Cl (6) P (7) F (8) H (9) S (10) Br (11) N
Match the noble gases – with their correct symbols.
Noble gases –
(a) Helium (b) Neon (c) Argon (d) Krypton (e) Xenon (f) Radon
Symbols – (1) Ar (2) Xe (3) Rn (4) He (5) Kr (6) Ne
Give a reason why elements are tabulated in a table called the ‘Periodic table’.
for easy in a simple and systematic manner. study Elements are tabulated in a table called ‘periodic table’
“Salient feature of periodic table”
- Horizontal rows are called periods
- vertical columns are called groups.
- Metallic elements are placed on the left side
- non-metallic elements are placed on the right.
- Noble gases are on the extreme right.
Give the names and symbols of the first twenty elements of the periodic table. Differentiate them into metals, non-metals, metalloids and noble gases.
Explain the term – molecules. Give three examples of atoms of the same element forming a molecule. State the atomicity of the same.
Atoms of the same element or different elements combine to form a molecule.
Atoms of the same element forming a molecule
Give one example of
(a) a triatomic molecule
(b) a polyatomic molecule.
(a) a triatomic molecule-O3 (Ozone)
(b) a polyatomic molecule.-P5 (sulphur)
Explain the term compounds. Give the example of a compound containing
(a) hydrogen and oxygen
(b)carbon and oxygen
(c) nitrogen and oxygen
(d) calcium and oxygen.
compound – A pure substance made up of two or more different elements combined chemically in a fixed ratio is called compound.
Example of a compound
(a) Water = H2O
(b) Carbon dioxide, = CO2
(c) Nitrogen dioxide, = NO2
(d) Calcium oxide, = CaO
State two characteristics of water which prove that it is a – compound.
Two Characteristics of compounds which confirm that it is a compound.
- It is made of hydrogen and Oxygen in fix ratio
H2 + O = H2O (water)
- The properties of the water are different from the properties of the components hydrogen and oxygen in water.
Explain the terms ‘chemical formula\ State what a chemical formula denotes.
- Chemical formula is a Symbolic representation of a substance ( element or compound)
- Chemical formula denotes the number of atoms present in a compound.
Give the symbols and the number of atoms of each element present in
(a) sodium chloride
(c) carbon dioxide
(d) zinc chloride.
(a) sodium chloride
Sodium – Na, Chlorine – Cl ,
No. of atoms of Sodium – 1
No. of atoms of Chlorine – 1
Formula = NaCl
Hydrogen – H, Oxygen – O
No. of atoms of Hydrogen – 2
No. of atoms of oxygen – 1
Formula = H2O
(c) Carbon dioxide
Carbon – C, Oxygen – O
No. of atoms of carbon – 1
No. of atoms of oxygen – 2
Formula = CO2
(d) Zinc chloride
Zinc – Zn, Chlorine – Cl
No. of atoms of zinc – 1
No. of atoms of chlorine – 2
Formula = ZnCl3
For writing a chemical formula – ‘symbols’ and combining capacity of an element with hydrogen i.e. ‘valency’ should be known. Explain the term – combining capacity of an element i.e. valency.
The combining power of an element especially as measured by the number of hydrogen atoms can combine or displace with the element
State what are radicals. Give the names of the radicals –
A radical is an atom or group of atom of same or different elements that behaves in the manner of positive or negative ions.
(a) NO3 – nitrate
(b) OH – hydroxide
(c) SO4 – sulphate
(d) CO3 – carbonate
Match the symbols of metallic elements – with their correct combining power or capacity.
Combining power or capacity – A : 3 ; B : 2 ; C : 1. (positive valencies)
(a) K — Valency-1 (C)
(b) Zn — Valency-2 (B)
(c) Al — Valency-3 (A)
(d) Na— Valency-1 (C)
(e) Ca — Valency-2 (B)
Match the symbols of non-metallic elements with their correct combining power or capacity.
Combining power or capacity A : 3; B : 2; C : 1. (negative valencies)
(a) O — Valency-2 (B)
(b) S — Valency-2 (B)
(c) Cl — Valency-1 (C)
Match the symbols of – radicals – with their correct combining power or capacity, (valency).
Combining power or capacity – A : 3; B : 2; C : 1. (negative valency)
(a) OH— Valency- 1 (C)
(b) SO4 — Valency- 2 (B)
(c) NO3— Valency- 1 (C)
(d) CO3 — Valency- 2 (B)
Write the formula of the compound formed – given “symbols and combining power or capacity (valency) of each element in the compound.
(a) K1+ Cl1-
(b) Na1+ Cl1-
(c) Ca2+ NO31-
Match the formulas of the following – gases – with their correct names :
Gases : (a) H2, (b) N2, (c) O2, (d) Cl2, (e) HCl, (f) NH3, (g) CO, (h) CO2, (i) SO2, (j) NO, (k) NO2
(1) Ammonia, (2) Nitrogen dioxide, (3) Oxygen, (4) Hydrogen, (5) Nitrogen, (6) Chlorine, (7) Carbon monoxide, (8) Sulphur dioxide, (9) Nitrogen monoxide, (10) Carbon dioxide, (11) Hydrogen chloride
|(e)||HCI||(11) Hydrogen Chloride|
|(g)||CO||(7) Carbon Monoxide|
|(h)||CO2||(10) Carbon Dioxide|
|(i)||SO2||(8) Sulphur Dioxide|
|(j)||NO||(9) Nitrogen Monoxide|
|(k)||NO2||(2) Nitrogen Dioxide|
Match the formulas of the following – acids – with their correct names
Acids : (a) HCl, (b) HNO3, (c) H2SO4, (d) H2CO3
Names : (1) Carbonic acid, (2) Sulphuric acid, (3) Hydrochloric acid, (4) Nitric acid
Match the formulas of the following – bases – with their correct names.
Bases : (a) NaOH, (b) KOH, (c) Ca(OH)2, (d) Zn(OH)2
Names : (1) Potassium hydroxide, (2) Zinc hydroxide, (3) Aluminium hydroxide, (4) Calcium hydroxide, (5) Sodium hydroxide
Complete the statements with the correct words.
(a) Acid’s – are chemicals whivh are _____ in taste and derived from plants and _____.
(b) Bases – are chemicals which are hydroxide (or oxides) of _____ eg. sodium hydroxide.
(c) Salts – are chemicals formed on reaction of a base with an _____ giving salt and water.
(a) Sour , minerals
In the chemical word equation – Zinc + Sulphuric acid → Zinc sulphate + Hydrogen
(a) State the reactants and products of the above reaction. What does the arrow indicate.
(b) The molecular equation is :
Zn + H2SO4 → ZnSO4 + H2[g]. State what [g] represents.
(a) Zinc and sulphuric acid are Reactants while Zinc sulphate and hydrogen are Products
The arrow indicates that the reaction has taken place.
(b) Symbol [g] represents a gaseous state of hydrogen.
Objective Type Questions -Elements & Compounds
Class-6 ICSE Chemistry Dalal New Simplified Solutions Chapter-2
Complete the statements given below by filling in the blank with the correct word/s.
- An element is a pure substance which cannot be broken down by physical or ______ methods.
- The basic unit of an element is an ______.
- Atom contains ________, with positively charged ________.
- Element _______ has the symbol derived from its Latin name ‘argentum’.
- From the elements – He, Br, Pt and O; the element which is metallic is ___, an inert element is ____, forms a triatomic molecule is O, is liquid at room temperature.
- From the elements nitrogen, chlorine, bromine, the element present in the atmosphere is nitrogen.
- Nucleus, protons
- Pt, He, Br
Match the statements in List I – 1 to 10 with their correct answers in List II – A to J.
|List I||List II|
|1. Fluorine and chlorine||A: Nitrogen|
|2. A diatomic molecule||B: Boron|
|3. A molecule containing the elements Hydrogen and oxygen||C: Reactants|
|4. A metalloid – showing properties of both metals and nonmetals||D: Chemical formula|
|5. The term used for the substances which Take part in the chemical reaction||E: Halogen|
|6. The term which represents a substance by means of symbols||F: water|
|7. The term used for substances formed As a result of a chemical reaction||G: Nitric oxide|
|8. A compound containing one atom of Zinc and two atoms of chlorine||H: products|
|9. The chemical name for nitrogen monoxide||I: Phosphorus|
|10. A polyatomic molecule||J: Zinc chloride|
|List I||List II|
|1. Fluorine and chlorine||E: Halogen|
|2. A diatomic molecule||A: Nitrogen|
|3. A molecule containing the elements Hydrogen and oxygen||F: water|
|4. A metalloid – showing properties of both metals and nonmetals||B: Boron|
|5. The term used for the substances which take part in the chemical reaction||C: Reactants|
|6. The term which represents a substance by means of symbols||D: Chemical formula|
|7. The term used for substances as a result of a chemical reaction||H: products|
|8. A compound containing one atom of zinc and two atoms of chlorine||J: Zinc chloride|
|9. The chemical name for nitrogen monoxide||G: Nitric oxide|
|10. A polyatomic molecule||I: Phosphorus|
Select the correct answer from the choice in brackets.
- The symbol of – mercury [Mg/Hg/Ag]
- The type of element-phosphorus [metallic/non-metallic/noble gas]
- The type of molecule – bromine [monoatomic/diatomic/triatomic]
- A compound [nitrogen/ozone/zinc chloride]
- The unreactive non-metallic element [chlorine/argon/sulphur]
- The negatively charged particle in an atom [protons/neutrons/electrons]
- The element which is malleable [sulphur/carbon/iron]
- An impure substance [element/mixture/compound]]
- An element which is a poor conductor of heat [copper/carbon/aluminium]
- A group of atoms of elements [ion/radical/combining power]
- Zinc chloride
Match the compounds in List I – 1 to 20 with their correct formulas from in List II – A to T.
1. Hydrochloric acid, 2. Potassium hydroxide, 3. Sulphuric acid, 4. Zinc hydroxide, 5. Sodium chloride, 6. Nitric acid, 7. Calcium hydroxide, 8. Carbonic acid, 9. Sodium hydroxide, 10. Copper sulphate, 11. Potassium chloride, 12. Calcium carbonate, 13. Magnesium suiphide, 14. Zinc sulphate, 15. Aluminium hydroxide, 16. Sodium carbonate, 17. Calcium sulphide, 18. Magncsium oxide, 19. Zinc oxide, 20. Ammonium chloride.
Class-6 ICSE Simplified Chemistry Chapter-2 Solutions
Explain the term mixtures. Give an example of mixtures of –
(a) two elements
(b) two compounds
(c) elements and compounds.
Mixture : combination of substance made up of two or more elements or compounds mechanically in any proportion called mixture
(a) Iron and sulphur
(b) Potassium chloride solution
(c) Sulphur, carbon and potassium nitrate makes gunpowder.
Differentiate between homogeneous and heterogeneous mixtures with suitable examples.
|Homogeneous Mixtures||Heterogeneous mixtures|
|The elements and compounds are uniformly mixed.||The elements and compounds are not uniformly mixed.|
|The properties of the mixture are the same in all compositions.||The properties differ at different compositions.|
|Copper and Zinc are two solids which make brass, which is solid. The elements cannot be distinguished.||In the mixture of Iron and Sulphur, iron can be easily separated using a magnet, the composition is not uniform.|
|Example – Alloy||Example – Oil and Air|
With reference to the mixture of iron and sulphur, state the main characteristics of mixture.
characteristics of mixture (Iron + Sulphur)
- Iron and mixed in any amount, which is not fixed.
- They retain original properties of iron and sulphur and do not change in the mixture.
- It can be separated physically by magnetization
Tabulate a comparative chart – to differentiate between elements, compounds and mixtures. Differentiate them with reference to
(a) the term
(d) separation of components.
|The term||It is the basic unit of matter which is a pure substance and cannot be broken down.||It is a pure substance made by a combination of two or more elements.||It is an impure substance made of a combination of two or more elements or compounds or both.|
|Existence||They can exist independently.||The elements are combined in a fixed ratio.||The elements and compounds are mixed in any ratio.|
|Properties||They have a definite set of properties.||The elements of a compound do not retain their properties.||The components of a mixture retain their properties.|
|Separation||Elements cannot be broken down into simpler substances.||Elements can be separated from compounds by chemical methods.||Components of mixture can be separated by physical methods.|
|Examples||Iron, sulphur||Water, carbon dioxide||Iron + Sulphur|
State the principle involved in separation of solid-solid mixtures by –
(b) magnetic separation
(a) Sieving – to separate solid components of different size.
Example – wheat and husk
(b) Magnetic separation – To separate mixtures which have one magnetic substance.
Example – iron & sulphur
(c) Sublimation – To separate solids which are sublimable.
Example – iodine and salt
State the principle involved in separation of solid-liquid mixtures by –
(a) sedimentation and decantation
(a) Sedimentation – To separate an insoluble solid component which is heavier than the liquid component in a mixture.
Example – Sand and water mixture.
(b) Filtration – to separate insoluble solid components by passing it through porous materials like filter paper.
Example – Chalk powder and water
(c) Evaporation – To separate a soluble solid component by evaporating the liquid in the mixture.
Example – sugar and water
Explain the term ‘sieving’. State the structure of a sieve and explain the separation of different sized particles by sieving.
- Sieving :- It is a method of separation which is used for separating solid components of different sized that are difficult to handpick.
- Sieve:- A sieve is a sheet of metal or plastic mesh which has small holes, which allow finer particles to pass through.
- Example, Wheat powder can be separated from soil using a sieve.
State what is meant by ‘magnetic separation of two mixtures’. Explain how iron particles can be separated from sulphur particles.
magnetic separation :- Magnetization is a technique of attracting magnetic substances. Magnetic separation means separating mixtures of two solids with one part which has magnetic properties. It is based on the difference in magnetic and non-magnetic substances.
In the mixture of iron and sulphur, iron particles get attracted to the magnet and separates from non-magnetic substances.
Give a reason why sublimable and non-sublimable substances can be separated easily, but two sublimable substance cannot.
Sublimable substances are substances that turn into vapour directly on heating, leaving behind the non-sublimable substance. Hence, it is easy to separate sublimable and non-sublimable substances and can be separated easily, while two sublimable substances turn into vapour on heating and cannot be separated on cooling either.
Explain the technique for separating – insoluble solid particles in a solid-liquid mixture.
The insoluble solid particles can be separated from liquid by filtration. A filter paper is made into a cone & placed in a funnel, the liquid flows through the cone and solid particles remain in the cone..
Differentiate between the terms sedimentation and decantation with a suitable experimental technique.
Sedimentation :-It is a process of settling down of the heavier particles present in a liquid mixture. example, in a mixture of sand and water, sand settles down at the bottom.
Decantation:- It is the process of separating liquid components of a mixture while the solid component has settled at the bottom as sediments, that is, transferring a liquid from another container .Ex-When water is separated from the mixture of sand and water
Explain how a solid component is separated in a soluble solid-liquid mixture.
A solid component is separated from a liquid by evaporation.
When a salt solution is heated, the water in the mixture evaporates and salt is left behind in solid form.
Draw a neat labelled diagram for separation of the following mixtures.
(a) Coarse sand from fine sand
(b) A magnetic particle from a non-magnetic particle
(c) Naphthalene from sodium chloride
(d) Chalk and water using a filter paper
(e) Sand and water without using a filter paper
(f) Common salt from a solution of common salt and water
Please refer the figure from your text book
State the technique involved in separating the following:
(a) Iodine crystals and potassium chloride
(b) Iron and chalk powder
(c) Potassium chloride from an aqueous solution of potassium chloride.
(d) Rice powder from soil particles
(e) Iron filings from pieces of copper wire
(f) Large diamonds from very small diamonds
(b) Magnetic separation
(e) Magnetic separation
Objective Type Questions of Mixture Exercise
Class-6 Dalal New Simplified ICSE Chemistry Solutions Chapter-2
Match the statements in List I with the correct answer in List II.
|List I||List II|
|1. Purification of water by adding alum||A: Sublimation|
|2. Sea water leaving behind common salt||B: Sieving|
|3. Separation of camphor and potassium chloride||C: Filtration|
|4. Separation of charcoal from a charcoal-water mixture||D: Sedimentation|
|5. Separation of bran and wheat flour||E: evaporation|
|List I||List II|
|1. Purification of water by adding alum||D: Sedimentation|
|2. Sea water leaving behind common salt||E: evaporation|
|3. Separation of camphor and potassium chloride||A: Sublimation|
|4. Separation of charcoal from a charcoal-water mixture||C: Filtration|
|5. Separation of bran and wheat flour||B: Sieving|
. State whether the following statements are true or false. If false write – the correct statement.
- Components in a mixture are present in a definite proportion.
- Mixture have no definite set of properties
- Components in a mixture can be separated by physical and chemical methods.
- Sodium chloride and water is an example of a mixture of compounds
- Heterogeneous mixtures have different composition and properties throughout the mixture
- False. Components in a mixture are present in a varying proportion.
- False. Components in a mixture can be separated by physical methods.
- False. Sodium chloride and water is an example of a mixture of compounds.
- A black non-metallic component of the mixture gunpowder.
- A physical method of separating iron from an iron-sulphur mixture.
- The component of the soluble solid-liquid mixture which is lost to the atmosphere on heating.
- The component of naphthalene-sodium chloride mixture which remains in the evaporating dish when heated together, covered with a funnel.
- A mixture of two immiscible liquids.
- Magnetic separation
- Liquid component i.e. water
- Sodium chloride
- Kerosene oil and water.
Give reasons for the following :
- Naphthalene and camphor can not be separated by sublimation.
- Sodium chloride cannot be separated out from its aqueous solution by filtration.
- Two varieties of wheat flour cannot be separated by sieving.
- Sulphur and charcoal powder cannot be separated by magnetic suspension.
- Both components of a soluble solid-liquid mixture cannot be recovered by evaporation.
- Both Naphthalene and camphor are sublimable solids and both sublime on heating.
- sodium chloride is soluble in water, which is why it cannot be separated through filtration.
- two varieties of wheat flour have same size particles both are them will pass the hole of seive
- Both Sulphur and charcoal are non-magnetic particles therefore cannot be separated by magnetic suspension.
- In evaporation, the liquid component is lost and evaporated as vapour which cannot be recovered.
.– : End of Class-6 Elements Compounds and Mixtures Dalal Simplified Solutions :–
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