Viraf J. Dalal solutions for New Simplified Middle School Chemistry [English] Class 8 chapter 5 - Language of Chemistry [Latest edition]

Explain the term ‘symbol’.

State a reason why the symbol of calcium is ‘Ca’ and of copper is ‘Cu’

Define the term ‘valency’.

With reference to water and ammonia as compounds respectively, state the valency of oxygen and nitrogen.

Give a reason – Magnesium [2, 8, 2] has valency 2+.

Explain the term ‘variable valency’.

Copper having electronic configuration 2,8,18,1 exhibits variable valency. Give a reason for the same and name the compound CuCI and CuCl₂.

State the valency of the following metallic element and write symbol with the valency
Potassium

State the valency of the following metallic element and write symbol with the valency
Sodium

State the valency of the following metallic element and write symbol with the valency
Calcium

State the valency of the following metallic element and write symbol with the valency
Magnesium

State the valency of the following metallic element and write symbol with the valency
Zinc

State the valency of the following metallic element and write symbol with the valency
Aluminium

State the valency of the following metallic element and write symbol with the valency
Chromium

Certain metal exhibit variable valencies which include valencies: 1+, 2+, 3+, and 4+.
State the variable valency of the following metal.
Copper
write symbol with the variable valency

Certain metal exhibit variable valencies which include valencies: 1+, 2+, 3+, and 4+.
State the variable valency of the following metal.
Silver
write symbol with the variable valency

Certain metal exhibit variable valencies which include valencies: 1+, 2+, 3+, and 4+.
State the variable valency of the following metal.
Mercury
write symbol with the variable valency

Certain metal exhibit variable valencies which include valencies: 1+, 2+, 3+, and 4+.
State the variable valency of the following metal.
Iron
write symbol with the variable valency

Certain metal exhibit variable valencies which include valencies: 1+, 2+, 3+, and 4+.
State the variable valency of the following metal.
Tin
write symbol with the variable valency

Certain metal exhibit variable valencies which include valencies: 1+, 2+, 3+, and 4+.
State the variable valency of the following metal.
Lead
write symbol with the variable valency

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Chloride

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Bromide

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Iodide

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Nitrate

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Hydroxide

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Bicarbonate

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Bisulphite

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Bisulphate

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Aluminate

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Permanganate

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Oxide

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Sulphide

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Sulphite

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Sulphate

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Carbonate

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Dichromate

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Zincate

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Plumbite

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Phosphate

State whether the following ion or radical given below of a non-metallic element exhibits valency: 1^–, 2^– or 3^–. (write the ion or radical with the correct valency).

Nitride

Differentiate between the terms – ‘Ion’ and ‘radical’ with suitable examples.

Write the chemical formula of the following compound in a step-by-step manner –

Potassium chloride

Write the chemical formula of the following compound in a step-by-step manner –

Sodium bromide

Write the chemical formula of the following compound in a step-by-step manner –

Potassium nitrate

Write the chemical formula of the following compound in a step-by-step manner –

Calcium hydroxide

Write the chemical formula of the following compound in a step-by-step manner –

Calcium bicarbonate

Write the chemical formula of the following compound in a step-by-step manner –

Sodium bisulphate

Write the chemical formula of the following compound in a step-by-step manner –

Potassium sulphate

Write the chemical formula of the following compound in a step-by-step manner –

Zinc hydroxide

Write the chemical formula of the following compound in a step-by-step manner –

Potassium permanganate

Write the chemical formula of the following compound in a step-by-step manner –

Potassium dichromate

Write the chemical formula of the following compound in a step-by-step manner –

Aluminium hydroxide

Write the chemical formula of the following compound in a step-by-step manner –

Magnesium nitride

Write the chemical formula of the following compound in a step-by-step manner –

Sodium zincate

Write the chemical formula of the following compound in a step-by-step manner –

Copper [II] oxide

Write the chemical formula of the following compound in a step-by-step manner –

Copper [I] sulphide

Write the chemical formula of the following compound in a step-by-step manner –

Iron [III] chloride

Write the chemical formula of the following compound in a step-by-step manner –

Iron [II] hydroxide

Write the chemical formula of the following compound in a step-by-step manner –

Iron [III] sulphur

Write the chemical formula of the following compound in a step-by-step manner –

Iron [III] oxide

What is the chemical equation. How is it represented?

Differentiate between a ‘word equation’ and a ‘molecular equation’ with a suitable example.

State the information provided by a chemical equation.

Chemical equations suffer from a number of limitations. State the main limitations of a chemical equation.

State what is a balanced equation with a relevant example. Give a reason why an equation is balanced with reference to the law of conservation of matter.

Write a balanced molecular equation for the following word equation:

\[\ce{Calcium + oxygen->Calcium oxide}\]

Write a balanced molecular equation for the following word equation:

\[\ce{Calcium + water->Calcium hydroxide + hydrogen}\]

Write a balanced molecular equation for the following word equation:

\[\ce{Zinc + sulphuric acid->Zinc sulphate + hydrogen}\]

Write a balanced molecular equation for the following word equation:

\[\ce{Lead sulphate + ammonium hydroxide->Ammonium sulphate + lead hydroxide}\]

Write a balanced molecular equation for the following word equation:

\[\ce{Copper hydroxide + nitric acid->Copper nitrate + water}\]

Write a balanced molecular equation for the following word equation:

\[\ce{Lead nitrate + sodium chloride->Sodium nitrate + lead chloride}\]

Balance the following equation:

\[\ce{P + O2->P2O5}\]

Balance the following equation:

\[\ce{Na2O + H2O->NaOH}\]

Balance the following equation:

\[\ce{K + H2O->KOH + H2}\]

Balance the following equation:

\[\ce{Fe + H2O⇌Fe3O4 + H2}\]

Balance the following equation:

\[\ce{CaO + HCl->CaCl2 + H2O}\]

Balance the following equation:

\[\ce{Fe + Cl2->FeCl3}\]

Balance the following equation:

\[\ce{Al + H2O->Al2O3 + H2}\]

Balance the following equation:

\[\ce{Al + H2SO4->Al2(SO4)3 + H2}\]

Balance the following equation:

\[\ce{Fe2O3 + H2->Fe + H2O}\]

Balance the following equation:

\[\ce{C + H2SO4->CO2 + H2O + SO2}\]

Balance the following equation:

\[\ce{Pb3O4->PbO + O2}\]

Balance the following equation:

\[\ce{Al + O2->Al2O3}\]

Balance the following equation:

\[\ce{NO + O2->NO2}\]

Balance the following equation:

\[\ce{ZnS + O2->ZnO + SO2}\]

Balance the following equation:

\[\ce{Pb3O4 + HCl->PbCl2 + H2O + Cl2}\]

Balance the following equation:

\[\ce{ZnO + NaOH->Na2ZnO2 + H2O}\]

Balance the following equation:

\[\ce{H2S + Cl2->S + HCl}\]

Balance the following equation:

\[\ce{FeCl3 + NaOH->NaCl + Fe(OH)3}\]

Balance the following equation:

\[\ce{Fe2O3 + CO->Fe + CO2}\]

Balance the following equation:

\[\ce{KHCO3->K2CO3 + H2O + CO2}\]

Balance the following equation:

\[\ce{CuO + NH3->Cu + H2O + N2}\]

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

The formula of silver [I] chloride is ________.

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

The basic unit of an element is a/an ________.

Complete the statement given below by filling in the blanks with the correct words.

Atoms contain ________ 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 ‘plumbum’.

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 forms a polyatomic molecule is ________ and which is liquid at room temperature is ________.

Complete the statement given below by filling in the blanks with the correct words.

The valency of iron in FeO is _______ of chlorine [chloride] in CaCl₂ is ________ and of dichromate in K₂ Cr₂  O₇ is ________.

Match the statements – 1 to 10 below with their correct answers from – A to J.

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

Underline the incorrectly balanced compound equation and rewrite the correct equation.

\[\ce{2Na + 3H2O->2NaOH + H2}\]

Underline the incorrectly balanced compound equation and rewrite the correct equation.

\[\ce{4P + 4O2->2P2O5}\]

Underline the incorrectly balanced compound equation and rewrite the correct equation.

\[\ce{Fe2O3 + 2H2->2Fe + 3H2O}\]

Underline the incorrectly balanced compound equation and rewrite the correct equation.

\[\ce{2Al + 2H2SO4->Al2(SO4)3 + 3H2}\]

Underline the incorrectly balanced compound equation and rewrite the correct equation.

\[\ce{N2 + 3H2⇌NH3}\]

Underline the incorrectly balanced compound equation and rewrite the correct equation.

\[\ce{ZnO + 3NaOH->Na2ZnO2 + H2O}\]\

Underline the incorrectly balanced compound equation and rewrite the correct equation.

\[\ce{FeCl3 + 3NH4OH->2NH4Cl + Fe(OH)3}\]

Underline the incorrectly balanced compound equation and rewrite the correct equation.

\[\ce{FeS + 2HCl + 2FeCl2 + H2S}\]

Underline the incorrectly balanced compound equation and rewrite the correct equation.

\[\ce{3NH3 + H2SO4->(NH4)2SO4}\]

Underline the incorrectly balanced compound equation and rewrite the correct equation.

\[\ce{PbO2 + 4HCl->PbCl2 + H2O + Cl2}\]