Viraf J. Dalal solutions for New Simplified Middle School Chemistry [English] Class 7 chapter 5 - Language of Chemistry [Latest edition]

Write word equation for the following molecular equation:

CuCo₃ → CuO + CO₂ [g]

Word equation:

State the characteristics or indications occurring in the above reaction.

Write word equation for the following molecular equation:

\[\ce{CaCO3 + 2HCl ->[\triangle] CaCl2 + H2O + CO2 [g]}\]

Word equation:

State which characteristic does [g] in the above reaction indicate. The word equation of:

Write word equation for the following molecular equation:

\[\ce{NH3 [g] + HCl [g] ⇌ NH4Cl [s]}\]

Word equation:
State which characteristic is observed in the above reaction.

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

Write word equation for the following molecular equation:

Na₂SO₃ + 2HCl [dil.] → 2NaCl + H₂O + SO₂ [g] 

Write word equation for the following molecular equation:

FeSO₄ + 2NaOH →Na₂SO₄ + Fe(OH)₂ ↓

Word equation:

State why [↓] indication is seen after Fe(OH)₂ and not after Na₂SO4

Write word equation for the following molecular equation:

\[\ce{N2 + 3H2 ⇌[Fe - 450°C][200 atoms] 2NH3 + \triangle}\]

Word equation:
State why [+ Δ] indication is seen after NH₃.
State what 200 atmospheres – indicates.
State the function of Fe in the above reaction.

Write word equation for the following molecular equation:

\[\ce{H2 [g] + Cl2 [g] ->[sunlight] 2HCl}\]

Word equation:

State which form of energy is utilised in the above chemical reaction.

Write word equation for the following molecular equation:

AgN0₃ + HCI → HNO₃ + AgCl ↓

Word equation:

State whether AgCl is soluble or insoluble in HN0₃.

Write word equation for the following molecular equation:

CaO + H₂0 → Ca (OH)₂ + Δ

Word equation:

State why [+ Δ ] is not written in the reaction, if ZnO reacts with H2O.

Write word equation for the following molecular equation:

\[\ce{CuSO4 + 2NaOH -> Na2SO4 + Cu(OH)2↓}\]

Word equation:

State the colour of the products.

Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.

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.

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 are heated – copper carbonate.

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 are heated – zinc carbonate.

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 are heated – mercury [II] oxide.

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 are heated –  lead [IV] oxide.

Give a balanced equation for addition of iron to copper [II] sulphate solution. State the change in colour seen.

In certain reaction 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 reactant.

\[\ce{C +2S -> CS2}\]

In certain reaction 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 reactant.

NH₃ + HCl ⇌ NH₄Cl 

In certain reaction 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 reactant.

2H₂ + O₂ → 2H₂O

In certain reaction 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 reactant.

\[\ce{2H2O ->[electric][current] 2H2 + O2}\]

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

In certain reaction an insoluble solid called precipitate is formed. State the colour and name of the precipitate formed in the following reaction involving addition of:

Dilute hydrochloric acid to silver nitrate.

In certain reaction an insoluble solid called precipitate is formed. State the colour and name of the precipitate formed in the following reaction involving addition of:

Iron [II] sulphate to sodium hydroxide.

In certain reaction an insoluble solid called precipitate is formed. State the colour and name of the precipitate formed in the following reaction involving addition of:

Iron [III] chloride to ammonium hydroxide.

In certain reaction an insoluble solid called precipitate is formed. State the colour and name of the precipitate formed in the following reaction involving addition of:

Copper [II] sulphate to sodium hydroxide.

In certain reaction an insoluble solid called precipitate is formed. State the colour and name of the precipitate formed in the following reaction involving addition of:

Lead nitrate to ammonium hydroxide.?

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.

Give one example in the case where supplying energy [given below] is necessary for a chemical reaction.

Heat energy

Give one example in the case where supplying energy [given below] is necessary for a chemical reaction.

Light energy

Give one example in the case where supplying energy [given below] is necessary for a chemical reaction.

Electrical energy

Give one example in the case where supplying energy [given below] is necessary for a chemical reaction.

Pressure

Give one example in the case where supplying energy [given below] is necessary for a chemical reaction.

Catalyst

Representation of the results of a chemical change – is a chemical equation.

For the equation: FeCl₃ + 3NH₄OH 3NH₄Cl + Fe(OH)₃ ↓

Answer the following:

Write the word equation for the above molecular equation.

Representation of the results of a chemical change – is a chemical equation.

For the equation: FeCl₃ + 3NH₄OH 3NH₄Cl + Fe(OH)₃ ↓

Answer the following:

Is the equation given above a balanced equation. Give reasons.

Representation of the results of a chemical change – is a chemical equation.

For the equation: FeCl₃ + 3NH₄OH 3NH₄Cl + Fe(OH)₃ ↓

Answer the following:

Name the reactants and the products in the above equation.

Representation of the results of a chemical change – is a chemical equation.

For the equation: FeCl₃ + 3NH₄OH 3NH₄Cl + Fe(OH)₃ ↓

Answer the following:

What is the indications of the arrow between the reactants and the products and of the arrow pointing downwards at the end.

Give word equation for the following chemical reaction and give the names of the product formed.

Zn + 2HC1→ ZnCl₂ + H₂

Give word equation for the following chemical reaction and give the names of the product formed.

\[\ce{CuO + H2SO4 -> CuSO4 + H2O}\]

Give word equation for the following chemical reaction and give the names of the product formed.

Zn + S → ZnS

Give word equation for the following chemical reaction and give the names of the product formed.

ZnCO₃ → ZnO + CO₂

Give word equation for the following chemical reaction and give the names of the product formed.

NH₃ + HCl→ NH₄Cl

Select the correct answer for the following options:

The black residue obtained on heating copper carbonate.

Select the correct answer for the following options:

The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.

Select the correct answer for the following options:

The gas obtained when potassium chlorate is heated in the presence of a catalyst.

Select the correct answer for the following options:

The pale blue precipitated obtained when copper [II] sulphate reacts with sodium hydroxide.

Select the correct answer for the following options:

The gas which reacts with oxygen to give a neutral liquid.

Give a word equation for the following reaction.

Two solids which combine on heating, to give a liquid.

Give a word equation for the following reaction.

Two gases which combine to give a solid.

Give a word equation for the following reaction.

A compound which on heating shows – colour change from brown to yellow.

Give a word equation for the following reaction.

A salt which reacts with ammonium hydroxide to give a reddish brown precipitate.

Give a word equation for the following reaction.

An exothermic reaction where both the reactants are gases, one of which is oxygen.

Name the following:

The silvery residue obtained on heating mercury [II] oxide.

Name the following:

The gas evolved when a dilute acid is added to chalk [limestone].

Name the following:

Two non-metal which react explosively when brought in close contact.

Name the following:

Two gases which react under pressure in presence of a catalyst at elevated temperatures to give a gaseous product.

Name the following:

A catalyst which increases the rate of a chemical reaction.

Give reason for the following:

Even though rusting is an exothermic reaction, the heat evolved when an iron nail rusts is unnoticeable.

Give reason for the following:

Electrolytic decomposition of water is a reaction involving change of state.

Give reason for the following:

A characteristic change of colour is seen when a piece of iron is added to copper [II] sulphate solution.

Give reason for the following:

The catalytic oxidation of sulphur dioxide to sulphur trioxide is represented by a double arrow {⇌} 
between the reactants and products, formed in the chemical reaction.

Give reason for the following:

Silver salts are kept in dark coloured bottles.

Write word equation for the following chemical reaction given below. Also state the observation seen in the case.

\[\ce{ZnCo3->[\triangle] ZnO + CO2}\]

Write word equation for the following chemical reaction given below. Also state the observation seen in the case.

NaCl + AgNo₃ → AgCU ↓ + NaN0₃

Write word equation for the following chemical reaction given below. Also state the observation seen in the case.

\[\ce{Na2SO3 + 2HCl ->[\triangle] 2NaCl + H2O + SO2}\]

Write word equation for the following chemical reaction given below. Also state the observation seen in the case.

\[\ce{2SO2 + O2 ⇌[V2O5][450°C] 2SO3}\]

Write word equation for the following chemical reaction given below. Also state the observation seen in the case.

Pb(NO3)₂ + 2NH₄OH → 2NH₄N0₃ + Pb(OH)_2↓