[1 Mark Question Answer]

Question 11 Mark

Give an example of a reaction where the following is involved .
High pressure is required

Answer

$\mathrm{N}_2+3 \mathrm{H}_2 \stackrel{\text { Above } 200 \mathrm{~atm}}{\rightleftharpoons} 2 \mathrm{NH}_3$

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Question 21 Mark

Give an example of a reaction where the following is involved .
Absorption of heat

Answer

$\mathrm{C}+2 \mathrm{~S} \xrightarrow{\Delta} \mathrm{CS}_2$

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Question 31 Mark

Give an example of a reaction where the following is involved .
Evolution of heat

Answer

$C + O_2 → CO_2 +$ Heat

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Question 41 Mark

nitrate which produces brown gas on heating.

Answer

Lead nitrate

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Question 51 Mark

Name a compound which produces carbon dioxide on heating.

Answer

Zinc carbonate

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Question 61 Mark

Name a nitrate which produces oxygen as the only gas.

Answer

Sodium nitrate

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Question 71 Mark

Name a carbonate which do not decompose on heating.

Answer

Sodium carbonate

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Question 81 Mark

What do you observe? When
Sodium chloride solution is added to silver nitrate solution.

Answer

When sodium chloride is added to the silver nitrate solution, a white curdy precipitate of silver chloride is formed.

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Question 91 Mark

What do you observe? When
Water is added to the quick lime.

Answer

Quick lime reacts vigorously with water to produce slaked lime, i.e. calcium hydroxide.

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Question 101 Mark

What do you observe? When
Barium chloride is added to sodium sulphate solution

Answer

A white insoluble precipitate of barium sulphate is formed.

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Question 111 Mark

What do you observe? When $H_2S$ gas is passed through copper sulphate solution.

Answer

When hydrogen sulphide is passed through a blue solution of copper sulphate, a black precipitate of copper sulphide is obtained, and sulphuric acid so formed remains in the solution.

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Question 121 Mark

What do you observe? When Hydrogen peroxide is exposed to sunlight.

Answer

Hydrogen peroxide breaks down to form water and oxygen gas along with heat energy.

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Question 131 Mark

What do you observe? When
Silver chloride is exposed to sunlight.

Answer

Due to thermal decomposition, silver chloride breaks down into silver and chloride.

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Question 141 Mark

What do you observe? When
Lead nitrate is heated.

Answer

Lead nitrate decomposes on heating, leaving a yellow residue of lead monoxide, and brown nitrogen dioxide and colourless oxygen gases are evolved.

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Question 151 Mark

Complete and balance the following reaction:
$ \mathrm{NH}_3+\mathrm{O}_2 \xrightarrow{\Delta} $

Answer

$\mathrm{NH}_3+\mathrm{O}_2 \xrightarrow{\mathrm{Pt}} 4 \mathrm{NO}+6 \mathrm{H}_2 \mathrm{O}$

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Question 161 Mark

Complete and balance the following reaction:
$\mathrm{Pb}\left(\mathrm{NO}_3\right)_2 \xrightarrow{\Delta} $

Answer

$\mathrm{Pb}\left(\mathrm{NO}_3\right)_2 \xrightarrow{\Delta} 2 \mathrm{PbO}+4 \mathrm{NO}_2+\mathrm{O}_2$

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Question 171 Mark

Complete and balance the following reaction:
$\mathrm{CuCO}_3 \xrightarrow{\Delta}$

Answer

$\mathrm{CuCO}_3 \xrightarrow{\Delta} \mathrm{CuO}(\mathrm{s})+\mathrm{CO}_2(\mathrm{~g})$

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Question 181 Mark

Complete and balance the following reaction:
$Pb(NO_3)_2 + KI →$

Answer

$Pb(NO_3)_2 + 2KI →2KNO_3 + PbI_2$

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Question 191 Mark

Complete and balance the following reaction:
$NaCl_{(aq)} + AgNO_{3(aq)} →$

Answer

$NaCl_{(aq)} + AgNO_{3(aq)} → AgCl_{(aq)}+ NaNO_{3(aq)}$

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Question 201 Mark

Give an example of double displacement reaction, where a gas is evolved.

Answer

$\mathrm{Na}_2 \mathrm{~S}+2 \mathrm{HCI} \longrightarrow 2 \mathrm{NaCI}+\mathrm{H}_2 \mathrm{~S} \uparrow$

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Question 211 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$CaCO_3→ CaO+ CO_2$

Answer

$CaCO_3 → CaO+ CO_2$
Decomposition reaction

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Question 221 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$AgNO_3 + NaCl → AgCl + NaNO_3$

Answer

$AgNO_3 + NaCl → AgCl + NaNO_3$
Double decomposition reaction

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Question 231 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$PbO + 2HNO_3→ Pb(NO_3) + 2H_2O$

Answer

$PbO + 2HNO_3 → Pb(NO_3) + 2H_2O$
Neutralisation reaction

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Question 241 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$NH_4Cl → NH_3 + HCl$

Answer

$NH_4Cl → NH_3 + HCl$
Decomposition reaction

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Question 251 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$CuO+H_2→ Cu+ H_2O$

Answer

$CuO+H_2 → Cu+ H_2O$
Displacement reaction

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Question 261 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$KNO_3 + H_2SO_4→ HNO_3 + KHSO_4$

Answer

$KNO_3 + H_2SO_4→ HNO_3 + KHSO_4$
Double decomposition reaction

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Question 271 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$2H_2O_2→ 2H_2O + O_2$

Answer

$2H_2O_2 → 2H_2O + O_2$
Decomposition reaction

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Question 281 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$2KClO_3→ 2KCl + 3O_2$

Answer

$2KClO_3 → 2KCl + 3O_2$
Decomposition reaction

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Question 291 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$PbO_2 + SO_2→ PbSO_4$

Answer

$PbO_2 + SO_2 → PbSO_4$
Combination reaction

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Question 301 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$Fe + CuSO_4→ FeSO_4 + Cu$

Answer

$Fe + CuSO_4 → FeSO_4 + Cu$
Displacement reaction

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Question 311 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$2HgO → 2Hg + O_2$

Answer

$2HgO → 2Hg + O_2$
Decomposition reaction

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Question 321 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$NaOH + HCl → NaCl + H_2O$

Answer

$NaOH + HCl → NaCl + H_2O$
Neutralisation reaction

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Question 331 Mark

State the type of reactions for the following represent and balance the ones that are not balanced.
$Cl_2 + 2KBr → 2KCl + Br_2$

Answer

$Cl_2 + 2KBr → 2KCl + Br_2$
Displacement reaction

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Question 341 Mark

Give reason for the following:
Colourless concentrated sulphuric acid in a test tube changes to blue on adding a small piece of copper to it.

Answer

Copper displaces hydrogen from sulphuric acid and forms blue-coloured copper sulphate and hydrogen gas is evolved.

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Question 351 Mark

Give reason for the following:
Blue solution of copper sulphate changes to green when a piece of iron is added to this solution.

Answer

This is because the blue colour of the copper sulphate solution fades and eventually turns into light green due to the formation of ferrous sulphate.

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Question 361 Mark

Give reason for the following:
Molybdenum is used in the manufacture of ammonia.

Answer

Molybdenum increases the efficiency of the catalyst iron used in the manufacture of ammonia.

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Question 371 Mark

Give reason for the following:
Silver nitrate solution is kept in coloured bottles.

Answer

Silver nitrate solution is kept in brown bottles in the laboratory because it decomposes in the presence of light.

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Question 381 Mark

Write the chemical reaction where the following changes are observed.
Physical state is changed

Answer

$\mathrm{Nh}_{3(g)}+\mathrm{HCI}_{(g)} \rightleftharpoons \mathrm{NH}_4 \mathrm{CI}_{(s)}$

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Question 391 Mark

Write the chemical reaction where the following changes are observed.
Precipitate is formed

Answer

$\mathrm{NaCI}_{(s)}+\mathrm{AgNO}_{3(s)} \longrightarrow \mathrm{AgCI} \downarrow+\mathrm{NaNO}_{3(a q)}$

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Question 401 Mark

Write the chemical reaction where the following changes are observed.
Colour change is noticed

Answer

$\mathrm{Fe}+\underset{\text { Blue solution }}{\mathrm{CuSO}_{4(a q)}} \longrightarrow \underset{\text { Green solution }}{\mathrm{FeSO}_4+\mathrm{Cu}}$

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Question 411 Mark

Write the chemical reaction where the following changes are observed.
Gas is evolved

Answer

$\mathrm{Zn}+\mathrm{H}_2 \mathrm{SO}_4 \longrightarrow \mathrm{ZnSO}_4+\mathrm{H}_2$

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Question 421 Mark

Give an example of the following chemical change.
A reaction where colour change is noticed

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Question 431 Mark

Give an example of the following chemical change.
Two solids combine to form a liquid

Answer

$C_{(s)} + 2S_{(g)} → CS_{2(l)}$

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Question 441 Mark

Give an example of the following chemical change.
Two gases combine to form white solid

Answer

$\mathrm{Nh}_{3(g)}+\mathrm{HCI}_{(g)} \rightleftharpoons \mathrm{NH}_4 \mathrm{CI}_{(s)}$

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Question 451 Mark

Give an example of a reaction where the following are involved
Catalyst

Answer

$2 \mathrm{KCIO}_3 \xrightarrow{\mathrm{MnO}_2} 2 \mathrm{KCI}+3 \mathrm{O}_2$

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Question 461 Mark

Give an example of a reaction where the following are involved
Pressure

Answer

$\mathrm{N}_2+3 \mathrm{H}_2 \underset{\text { Above } 200 \mathrm{~atm}}{\stackrel{\rightharpoonup}{\rightleftharpoons}} 2 \mathrm{NH}_3$

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Question 471 Mark

Give an example of a reaction where the following are involved:
Solution

Answer

$\mathrm{NaCl}(\mathrm{aq})+\mathrm{AgNO}_3(\mathrm{aq}) \longrightarrow \underset{\text { white ppt. }}{\mathrm{AgCl} \downarrow+\mathrm{NaNO}_3(\mathrm{aq})}$

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Question 481 Mark

Give an example of a reaction where the following are involved
Close contact

Answer

$\mathrm{PbNO}_{3(s)} \longrightarrow 2 \mathrm{Ki}_{(s)}+2 \mathrm{KNO}_{3(s)}+\mathrm{PbI}_{2(s)}$

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Question 491 Mark

Give an example of a reaction where the following are involved
Electricity

Answer

$2 \mathrm{H}_2 \mathrm{O} \xrightarrow{\text { Electricity }} 2 \mathrm{H}_2+\mathrm{O}_2$

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Question 501 Mark