Viraf J. Dalal solutions for New Simplified Middle School Chemistry [English] Class 6 chapter 2 - Elements, Compounds & Mixtures [Latest edition]

Classify substances into pure and impure substances in the form of a chart or tabulation.

Differentiate between the terms –
elements, compounds & mixtures.

The important physical properties of substances are colour, odour, nature, density & solubility in water.
Name – two coloured gases (with their colours)

The important physical properties of substances are colour, odour, nature, density & solubility in water.

Name – a gas with a pungent, choking odour which is lighter than air

The important physical properties of substances are colour, odour, nature, density & solubility in water.

Name - a poisonous gas almost as heavy as air.

Complete the statement – an element is a pure substance made up of ____________ 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 –

1. Metallic element
2. Non-metallic element
3. Metalloid
4. 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 the air _________
D: Shows properties of both metals and non-metals ___________

An atom of an element is denoted by a “symbol”. Explain the meaning of the term ‘symbol’. State a reason for representing the following element by its symbol.

Hydrogen by ‘H’

An atom of an element is denoted by a “symbol” Explain the meaning of the term ‘symbol’. State a reason for representing the following element by its symbol.

Helium by ‘He’

An atom of an element is denoted by a “symbol” Explain the meaning of the term ‘symbol’. State a reason for representing the following element by its symbol.

Copper by ‘Cu’

Match the metallic elements – with their correct symbols Metallic elements

Match the non-metallic elements – with their correct symbols. Non-metallic elements are:

Match the noble gases – with their correct symbols:

Give a reason why elements are tabulated in a table called the ‘Periodic table’.

Give the names and symbols of the first twenty elements of the periodic table.

Explain the term – molecules. Give three examples of atoms of the same element forming a molecule. State the atomicity of the same.

Give one example of a triatomic molecule

Give one example of a polyatomic molecule.

Explain the term compounds.

Give the example of a compound containing hydrogen and oxygen.

Give the example of a compound containing carbon and oxygen.

Give the example of a compound containing nitrogen and oxygen.

Give the example of a compound containing calcium and oxygen.

State two characteristics of water which prove that it is a – compound.

Explain the terms ‘chemical formula’.

State what a chemical formula denotes.

Give the symbol and the number of atoms of the following elements present in sodium chloride.

Give the symbol and the number of atoms of the following elements present in water.

Give the symbol and the number of atoms of the following elements present in carbon dioxide.

Give the symbol and the number of atoms of the following elements present in zinc chloride.

For writing a chemical formula – ‘symbols’ and combining capacity of an element with hydrogen i.e. ‘valency’ should be known. Explain the term – combining the capacity of an element i.e. valency.

State what are radicals. Give the names of the radicals –

(a) NO₃
(b) OH
(c) SO₄
(d) CO₃

Match the symbols of metallic elements – with their correct combining power or capacity.

(a) K
(b) Zn
(c) Al
(d) Na
(e) Ca
Combining power or capacity – A : 3 ; B : 2 ; C : 1. (positive valencies)

Match the symbols of non-metallic elements with their correct combining power or capacity.

(a) O
(b) S
(c) Cl

Combining power or capacity A : 3; B : 2; C : 1. (negative valencies)

Match the symbols of – radicals – with their correct combining power or capacity, (valency).

(a) OH
(b) So₄
(c) No₃
(d) Co₃

Combining power or capacity – A : 3; B : 2; C : 1. (negative valencies)

Write the formula of the compound formed – given symbols and combining power or capacity (valency) of the following element in the compound.

K¹⁺ Cl^1-

Write the formula of the compound formed – given symbols and combining power or capacity (valency) of the following element in the compound.

Na¹⁺ Cl^1-

Write the formula of the compound formed – given symbols and combining power or capacity (valency) of the following element in the compound.

Ca²⁺ NO₃^1-

Match the formulas of the following gases with their correct names :

Gases - (a) H₂ (b) N₂ (c) O₂ (d) Cl₂ (e) HCI (f) NH₃ (g) CO (h) CO₂ (i) SO₂ (j) NO (k) NO₂.

Names:

(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

Match the formulas of the following of acids with their correct names:
Acids – (a) HCI (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 of 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 statement with the correct words.
Acid’s are chemicals which are _____ in taste and derived from plants and ________.

Complete the statement with the correct words.
_______  are chemicals which are hydroxide (or oxides) of  ______  eg. sodium hydroxide.

Complete the statement with the correct words.
__________ are chemicals formed on reaction of a base with an _____ giving salt and water.

In the chemical word equation –

Zinc + Sulphuric acid → Zinc sulphate + Hydrogen.

State the reactants and products of the above reaction. What does the arrow indicate?

In the chemical word equation – Zinc + Sulphuric acid → Zinc sulphate + Hydrogen

The molecular equation is :

Zn + H₂SO₄ → ZnSO₄ + H₂[g].

State what [g] represents.

Complete the statement given below by filling in the blank with the correct word.
An element is a pure substance which cannot be broken down by physical or _________ methods.

Complete the statement given below by filling in the blank with the correct word.

The basic unit of an element is an __________.

Complete the statement given below by filling in the blanks with the correct words.
Atom contains ________ , with positively charged _____.

Complete the statement given below by filling in the blank with the correct word.
Element ______ has the symbol derived from its Latin name ‘Argentum’

Complete the statement given below by filling in the blanks with the correct words.
From the elements – He, Br, Pt, and O; the element which is metallic is ____, an inert element is ____, forms a triatomic molecule is ____, is liquid at room temperature is_ ___.

Complete the statement given below by filling in the blank with the correct word.
From the elements nitrogen, chlorine, bromine, the element present in the atmosphere is ________.

Match the statements in List I – 1 to 10 correct answers in List II-A to J.

Select the correct answer from the choice given below.
The symbol of mercury is

Select the correct answer from the choice given below.

The type of element-phosphorus

Select the correct answer from the choice given below.
The type of molecule- bromine

Select the correct answer from the choice given below.
A compound

Select the correct answer from the choice given below.
The unreactive non-metallic element

Select the correct answer from the choice given below.
The negatively charged particles in an atom

Select the correct answer from the choice given below.
The element which is malleable

Select the correct answer from the choice given below.
An impure substance

Select the correct answer from the choice given below.
An element which is a poor conductor of heat

Select the correct answer from the choice given below.
A group of atoms of elements

Match the compounds in List I – 1 to 20 with their correct formulas from in List II-A to T.

Explain the term mixtures.

Give an example of mixtures of two elements

Give an example of mixtures of two compounds

Give an example of mixtures of elements and compounds.

Differentiate between homogeneous and heterogeneous mixtures with suitable examples.

With reference to the mixture of iron and sulphur, state the main characteristics of the mixture.

Tabulate a comparative chart – to differentiate between elements, compounds, and mixtures. Differentiate them with reference to the term

Tabulate a comparative chart – to differentiate between elements, compounds, and mixtures. Differentiate them with reference to existence

Tabulate a comparative chart – to differentiate between elements, compounds, and mixtures. Differentiate them with reference to properties

Tabulate a comparative chart – to differentiate between elements, compounds, and mixtures. Differentiate them with reference to Separation of compound

State the principle involved in separation of solid-solid mixtures by sieving

State the principle involved in separation of solid-solid mixtures by magnetic separation

State the principle involved in separation of solid-solid mixtures by Sublimation

State the principle involved in separation of solid-liquid mixtures by sedimentation and decantation

State the principle involved in separation of solid-liquid mixtures by filtration

State the principle involved in separation of solid-liquid mixtures by evaporation

Explain the term ‘sieving’. State the structure of a sieve and explain the separation of different sized particles by sieving.

State what is meant by ‘magnetic separation of two mixtures’. Explain how iron particles can be separated from sulphur particles.

Give a reason why sublimable and non-sublimable substances can be separated easily, but two sublimable substance cannot.

Explain the technique for separating – insoluble solid particles in a solid-liquid mixture.

Differentiate between the terms sedimentation and decantation with a suitable experimental technique.

Explain how a solid component is separated in a soluble solid-liquid mixture.

Draw a neat labelled diagram for the separation of the following mixture.

Coarse sand from fine sand

Draw a neat labelled diagram for the separation of the following mixture.

A magnetic particle from a non-magnetic particle

Draw a neat labelled diagram for the separation of the following mixture.

Naphthalene from sodium chloride

Draw a neat labelled diagram for the separation of the following mixture.

Chalk and water using a filter paper

Draw a neat labelled diagram for the separation of the following mixture.

Sand and water without using a filter paper

Draw a neat labelled diagram for the separation of the following mixture.

Common salt from a solution of common salt and water

State the technique involved in separating the following:

Iodine crystals and potassium chloride

State the technique involved in separating the following:

Iron and chalk powder

State the technique involved in separating the following:

Potassium chloride from an aqueous solution of potassium chloride.

State the technique involved in separating the following:

Rice powder from soil particles

State the technique involved in separating the following:

Iron filings from pieces of copper wire

State the technique involved in separating the following:

Large diamonds from very small diamonds

Match the statements in List I with the correct answer in List II.

State whether the following statement is true or false. If false write – the correct statement.

Components in a mixture are present in a definite proportion.

State whether the following statement is true or false. If false write – the correct statement.

Mixture has no definite set of properties.

State whether the following statement is true or false. If false write – the correct statement.

Components in a mixture can be separated by physical and chemical methods.

State whether the following statement is true or false. If false write – the correct statement.

Sodium chloride and water is an example of a mixture of elements and compounds.

State whether the following statement is true or false. If false write – the correct statement.

Heterogeneous mixtures have different composition and properties throughout the mixture.

Name the following

A black non-metallic component of the mixture gunpowder.

Name the following:

A physical method of separating iron from an iron-sulfur mixture.

Name the following:

The component of the soluble solid-liquid mixture, which is lost to the atmosphere on heating.

Name the following:

The component of a naphthalene-sodium chloride mixture, which remains in the evaporating dish when heated together, covered with a funnel.

Name the following:

A mixture of two immiscible liquids

Give reasons for the following:

Naphthalene and camphor cannot be separated by sublimation.

Give reasons for the following:

Sodium chloride cannot be separated out from its aqueous solution by filtration.

Give reasons for the following:

Two varieties of wheat flour cannot be separated by sieving.

Give reasons for the following:

Sulphur and charcoal powder cannot be separated by magnetic separation.

Give reasons for the following:

Both components of a soluble solid-liquid mixture cannot be recovered by evaporation.