Question 1

Question 10State the information provided by a chemical equation. Chemical equations suffer from a number of limitations. State the main limitations of a chemical equation.

Accepted Answer

Information provided by a chemical equation :The formulas & symbols of the reactants & products.The physical state of the substance whether it is solid, liquid or gas.The special conditions required such as heat, catalyst, direction of reaction.Tells the ratio in which the substances react in a balanced equation.Chemical equation do not tell us about:The physical states of the reactants & products - hence [(s) for solids, (g) for gas may be added]The conditions such as temperature, pressure or catalyst which affect the reaction.The concentration of the reactants & products hence [(dil.) dilute & (conc) concentrated may be added.]The nature of the chemical reaction.The speed of the reaction.The heat changes accompanying the reaction.The completion of the reaction.

Question 2

Question 13Balance the following equations:(a) P + O2 ⟶ P2O5(b) Na2O + H2O ⟶ NaOH(c) K + H2O ⟶ KOH + H2(d) Fe + H2O ⇌ Fe3O4 + H2(e) CaO + HCl ⟶ CaCl2 + H2O(f) Fe + Cl2 + FeCl3(g) Al + H2O ⟶ Al2O3 + H2(h) Al + H2SO4 ⟶ Al2(SO4)3 + H2(i) Fe2O3 + H2 ⟶ Fe + H2O(j) C + H2SO4 ⟶ CO2 + H2O + SO2(k) Pb3O4 ⟶ PbO + O2(l) Al + O2 ⟶ Al2O3(m) NO + O2 ⟶ NO2(n) ZnS + O2 ⟶ ZnO + SO2(o) Pb3O4 + HCl ⟶ PbCl2 + H2O + Cl2(p) ZnO + NaOH ⟶ Na2ZnO2 + H2O(q) H2S + Cl2 ⟶ S + HCl(r) FeCl3 + NaOH ⟶ NaCl + Fe(OH)3(s) Fe2O3 + CO ⟶ Fe + CO2(t) KHCO3 ⟶ K2CO3 + H2O + CO2(u) CuO + NH3 ⟶ Cu + H2O + N2

Accepted Answer

(a) 4P + 5O2 ⟶ 2P2O5(b) Na2O + H2O ⟶ 2NaOH(c) 2K + 2H2O ⟶ 2KOH + H2(d) 3Fe + 4H2O ⇌ Fe3O4 + 4H2(e) CaO + 2HCl ⟶ CaCl2 + H2O(f) 2Fe + 3Cl2 + 2FeCl3(g) 2Al + 3H2O ⟶ Al2O3 + 3H2(h) 2Al + 3H2SO4 ⟶ Al2(SO4)3 + 3H2(i) Fe2O3 + 3H2 ⟶ 2Fe + 3H2O(j) C + 2H2SO4 ⟶ + CO2 + 2H2O + 2SO2(k) 2Pb3O4 ⟶ 6PbO + O2(l) 4Al + 3O2 ⟶ 2Al2O3(m) 2NO + O2 ⟶ 2NO2(n) 2ZnS + 3O2 ⟶ 2ZnO + 2SO2(o) Pb3O4 + 8HCl ⟶ 3PbCl2 + 4H2O + Cl2(p) ZnO + 2NaOH ⟶ Na2ZnO2 + H2O(q) H2S + Cl2 ⟶ S + 2HCl(r) FeCl3 + 3NaOH ⟶ 3NaCl + Fe(OH)3(s) Fe2O3 + 3CO ⟶ 2Fe + 3CO2(t) 2KHCO3 ⟶ K2CO3 + H2O + CO2(u) 3CuO + 2NH3 ⟶ 3Cu + 3H2O + N2

Question 3

Question 8Write the chemical formula of the following compounds in a step-by-step manner(a) Potassium chloride(b) Sodium bromide(c) Potassium nitrate(d) Calcium hydroxide(e) Calcium bicarbonate(f) Sodium bisulphate(g) Potassium sulphate(h) Zinc hydroxide(i) Potassium permanganate(j) Potassium dichromate(k) Aluminium hydroxide(l) Magnesium nitride(m) Sodium zincate(n) Copper [II] oxide(o) Copper [I] sulphide(p) Iron [III] chloride(q) Iron [II] hydroxide(r) Iron [III] sulphide(s) Iron [III] oxide.

Accepted Answer

(a) Potassium chlorideStep 1 — Write each symbol with its valencyK1+↗Cl1−\text{K}^{1+} \phantom{\nearrow} \text{Cl}^{1-}K1+↗Cl1−Step 2 — Interchange the valenciesK21 ↘↙ Cl1⇒K11 ↘↙ Cl1\overset{\phantom{2}{1}}{\text{K}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{Cl}} \Rightarrow \underset{\phantom{1}{1}}{\text{K}} \space {\searrow}\mathllap{\swarrow} \space \underset{1}{\text{Cl}}K21 ↘↙ Cl1⇒11K​ ↘↙ 1Cl​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Potassium chloride : KCl\bold{KCl}KCl(b) Sodium bromideStep 1 — Write each symbol with its valencyNa1+↗Br1−\text{Na}^{1+} \phantom{\nearrow} \text{Br}^{1-}Na1+↗Br1−Step 2 — Interchange the valenciesNa21 ↘↙ Br1⇒Na11 ↘↙ Br1\overset{\phantom{2}{1}}{\text{Na}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{Br}} \Rightarrow \underset{\phantom{1}{1}}{\text{Na}} \space {\searrow}\mathllap{\swarrow} \space \underset{1}{\text{Br}} \[0.5em]Na21 ↘↙ Br1⇒11Na​ ↘↙ 1Br​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Sodium bromide : NaBr\bold{NaBr}NaBr(c) Potassium nitrateStep 1 — Write each symbol with its valencyK1+↗NO31−\text{K}^{1+} \phantom{\nearrow} \text{NO}_3^{1-}K1+↗NO31−​Step 2 — Interchange the valenciesK21 ↘↙ NO31⇒K11 ↘↙ NO31\overset{\phantom{2}{1}}{\text{K}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{NO}_3} \Rightarrow \underset{\phantom{1}{1}}{\text{K}} \space {\searrow}\mathllap{\swarrow} \space \underset{1}{\text{NO}_3} \[0.5em]K21 ↘↙ NO3​1​⇒11K​ ↘↙ 1NO3​​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Potassium nitrate : KNO3\bold{KNO}_\bold{3}KNO3​(d) Calcium hydroxideStep 1 — Write each symbol with its valencyCa2+↗OH1−\text{Ca}^{2+} \phantom{\nearrow} \text{OH}^{1-}Ca2+↗OH1−Step 2 — Interchange the valenciesCa22 ↘↙ OH1⇒Ca11 ↘↙ OH2\overset{\phantom{2}{2}}{\text{Ca}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{OH}} \Rightarrow \underset{\phantom{1}{1}}{\text{Ca}} \space {\searrow}\mathllap{\swarrow} \space \underset{2}{\text{OH}} \[0.5em]Ca22 ↘↙ OH1⇒11Ca​ ↘↙ 2OH​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Calcium hydroxide : Ca(OH)2\bold{Ca(OH)}_\bold{2}Ca(OH)2​(e) Calcium bicarbonateStep 1 — Write each symbol with its valencyCa2+↗HCO31−\text{Ca}^{2+} \phantom{\nearrow} \text{HCO}_3^{1-}Ca2+↗HCO31−​Step 2 — Interchange the valenciesCa22 ↘↙ HCO31⇒Ca11 ↘↙ HCO32\overset{\phantom{2}{2}}{\text{Ca}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{HCO}_3} \Rightarrow \underset{\phantom{1}{1}}{\text{Ca}} \space {\searrow}\mathllap{\swarrow} \space \underset{2}{\text{HCO}_3} \[0.5em]Ca22 ↘↙ HCO3​1​⇒11Ca​ ↘↙ 2HCO3​​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Calcium bicarbonate : Ca(HCO3)2\bold{Ca(HCO_\bold{3})_\bold{2}}Ca(HCO3​)2​(f) Sodium bisulphateStep 1 — Write each symbol with its valencyNa1+↗HSO41−\text{Na}^{1+} \phantom{\nearrow} \text{HSO}_4^{1-}Na1+↗HSO41−​Step 2 — Interchange the valenciesNa21 ↘↙ HSO41⇒Na11 ↘↙ HSO41\overset{\phantom{2}{1}}{\text{Na}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{HSO}_4} \Rightarrow \underset{\phantom{1}{1}}{\text{Na}} \space {\searrow}\mathllap{\swarrow} \space \underset{1}{\text{HSO}_4} \[0.5em]Na21 ↘↙ HSO4​1​⇒11Na​ ↘↙ 1HSO4​​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Sodium bisulphate : NaHSO4\bold{NaHSO}_4NaHSO4​(g) Potassium sulphateStep 1 — Write each symbol with its valencyK1+↗SO42−\text{K}^{1+} \phantom{\nearrow} \text{SO}_4^{2-}K1+↗SO42−​Step 2 — Interchange the valenciesK21 ↘↙ SO42⇒K12 ↘↙ SO41\overset{\phantom{2}{1}}{\text{K}} \space {\searrow}\mathllap{\swarrow} \space \overset{2}{\text{SO}_4} \Rightarrow \underset{\phantom{1}{2}}{\text{K}} \space {\searrow}\mathllap{\swarrow} \space \underset{1}{\text{SO}_4} \[0.5em]K21 ↘↙ SO4​2​⇒12K​ ↘↙ 1SO4​​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Potassium sulphate : K2SO4\bold{K_2SO_4}K2​SO4​(h) Zinc hydroxideStep 1 — Write each symbol with its valencyZn2+↗OH1−\text{Zn}^{2+} \phantom{\nearrow} \text{OH}^{1-}Zn2+↗OH1−Step 2 — Interchange the valenciesZn22 ↘↙ OH1⇒Zn11 ↘↙ OH2\overset{\phantom{2}{2}}{\text{Zn}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{OH}} \Rightarrow \underset{\phantom{1}{1}}{\text{Zn}} \space {\searrow}\mathllap{\swarrow} \space \underset{2}{\text{OH}} \[0.5em]Zn22 ↘↙ OH1⇒11Zn​ ↘↙ 2OH​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Zinc hydroxide : Zn(OH)2\bold{Zn(OH)_2}Zn(OH)2​(i) Potassium permanganateStep 1 — Write each symbol with its valencyK1+↗MnO41−\text{K}^{1+} \phantom{\nearrow} \text{MnO}_4^{1-}K1+↗MnO41−​Step 2 — Interchange the valenciesK21 ↘↙ MnO41⇒K11 ↘↙ MnO41\overset{\phantom{2}{1}}{\text{K}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{MnO}_4} \Rightarrow \underset{\phantom{1}{1}}{\text{K}} \space {\searrow}\mathllap{\swarrow} \space \underset{1}{\text{MnO}_4} \[0.5em]K21 ↘↙ MnO4​1​⇒11K​ ↘↙ 1MnO4​​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Potassium permanganate : KMnO4\bold{KMnO_4}KMnO4​(j) Potassium dichromateStep 1 — Write each symbol with its valencyK1+↗Cr2O72−\text{K}^{1+} \phantom{\nearrow} \text{Cr}_2\text{O}_7^{2-}K1+↗Cr2​O72−​Step 2 — Interchange the valenciesK21 ↘↙ Cr2O72⇒K12 ↘↙ Cr2O71\overset{\phantom{2}{1}}{\text{K}} \space {\searrow}\mathllap{\swarrow} \space \overset{2}{\text{Cr}_2\text{O}_7} \Rightarrow \underset{\phantom{1}{2}}{\text{K}} \space {\searrow}\mathllap{\swarrow} \space \underset{1}{\text{Cr}_2\text{O}_7} \[0.5em]K21 ↘↙ Cr2​O7​2​⇒12K​ ↘↙ 1Cr2​O7​​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Potassium dichromate : K2Cr2O7\bold{K_2Cr_2O_7}K2​Cr2​O7​(k) Aluminium hydroxideStep 1 — Write each symbol with its valencyAl3+↗OH1−\text{Al}^{3+} \phantom{\nearrow} \text{OH}^{1-}Al3+↗OH1−Step 2 — Interchange the valenciesAl23 ↘↙ OH1⇒Al11 ↘↙ OH3\overset{\phantom{2}{3}}{\text{Al}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{OH}} \Rightarrow \underset{\phantom{1}{1}}{\text{Al}} \space {\searrow}\mathllap{\swarrow} \space \underset{3}{\text{OH}} \[0.5em]Al23 ↘↙ OH1⇒11Al​ ↘↙ 3OH​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Aluminium hydroxide : Al(OH)3\bold{Al(OH)_3}Al(OH)3​(l) Magnesium nitrideStep 1 — Write each symbol with its valencyMg2+↗N3−\text{Mg}^{2+} \phantom{\nearrow} \text{N}^{3-}Mg2+↗N3−Step 2 — Interchange the valenciesMg22 ↘↙ N3⇒Mg13 ↘↙ N2\overset{\phantom{2}{2}}{\text{Mg}} \space {\searrow}\mathllap{\swarrow} \space \overset{3}{\text{N}} \Rightarrow \underset{\phantom{1}{3}}{\text{Mg}} \space {\searrow}\mathllap{\swarrow} \space \underset{2}{\text{N}} \[0.5em]Mg22​ ↘↙ N3⇒13Mg​ ↘↙ 2N​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Magnesium nitride : Mg3N2\bold{Mg_3N_2}Mg3​N2​(m) Sodium zincateStep 1 — Write each symbol with its valencyNa1+↗ZnO22−\text{Na}^{1+} \phantom{\nearrow} \text{ZnO}_2^{2-}Na1+↗ZnO22−​Step 2 — Interchange the valenciesNa21 ↘↙ ZnO22⇒Na12 ↘↙ ZnO21\overset{\phantom{2}{1}}{\text{Na}} \space {\searrow}\mathllap{\swarrow} \space \overset{2}{\text{ZnO}_2} \Rightarrow \underset{\phantom{1}{2}}{\text{Na}} \space {\searrow}\mathllap{\swarrow} \space \underset{1}{\text{ZnO}_2} \[0.5em]Na21 ↘↙ ZnO2​2​⇒12Na​ ↘↙ 1ZnO2​​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Sodium zincate : Na2ZnO2\bold{Na_2ZnO_2}Na2​ZnO2​(n) Copper [II] oxideStep 1 — Write each symbol with its valencyCu2+↗O2−\text{Cu}^{2+} \phantom{\nearrow} \text{O}^{2-}Cu2+↗O2−Step 2 — Interchange the valenciesCu22 ↘↙ O2⇒Cu22 ↘↙ O2\overset{\phantom{2}{2}}{\text{Cu}} \space {\searrow}\mathllap{\swarrow} \space \overset{2}{\text{O}} \Rightarrow \underset{\phantom{2}{2}}{\text{Cu}} \space {\searrow}\mathllap{\swarrow} \space \underset{2}{\text{O}} \[0.5em]Cu22 ↘↙ O2⇒22Cu​ ↘↙ 2O​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Copper [II] oxide : CuO\bold{CuO}CuO(o) Copper [I] sulphideStep 1 — Write each symbol with its valencyCu1+↗S2−\text{Cu}^{1+} \phantom{\nearrow} \text{S}^{2-}Cu1+↗S2−Step 2 — Interchange the valenciesCu11 ↘↙ S2⇒Cu12 ↘↙ S1\overset{\phantom{1}{1}}{\text{Cu}} \space {\searrow}\mathllap{\swarrow} \space \overset{2}{\text{S}} \Rightarrow \underset{\phantom{1}{2}}{\text{Cu}} \space {\searrow}\mathllap{\swarrow} \space \underset{1}{\text{S}} \[0.5em]Cu11 ↘↙ S2⇒12Cu​ ↘↙ 1S​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Copper [I] sulphide : Cu2S\bold{Cu_2S}Cu2​S(p) Iron [III] chlorideStep 1 — Write each symbol with its valencyFe3+↗Cl1−\text{Fe}^{3+} \phantom{\nearrow} \text{Cl}^{1-}Fe3+↗Cl1−Step 2 — Interchange the valenciesFe23 ↘↙ Cl1⇒Fe11 ↘↙ Cl3\overset{\phantom{2}{3}}{\text{Fe}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{Cl}} \Rightarrow \underset{\phantom{1}{1}}{\text{Fe}} \space {\searrow}\mathllap{\swarrow} \space \underset{3}{\text{Cl}} \[0.5em]Fe23 ↘↙ Cl1⇒11Fe​ ↘↙ 3Cl​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Iron [III] chloride : FeCl3\bold{FeCl_3}FeCl3​(q) Iron [II] hydroxideStep 1 — Write each symbol with its valencyFe2+↗OH1−\text{Fe}^{2+} \phantom{\nearrow} \text{OH}^{1-}Fe2+↗OH1−Step 2 — Interchange the valenciesFe22 ↘↙ OH1⇒Fe11 ↘↙ OH2\overset{\phantom{2}{2}}{\text{Fe}} \space {\searrow}\mathllap{\swarrow} \space \overset{1}{\text{OH}} \Rightarrow \underset{\phantom{1}{1}}{\text{Fe}} \space {\searrow}\mathllap{\swarrow} \space \underset{2}{\text{OH}} \[0.5em]Fe22 ↘↙ OH1⇒11Fe​ ↘↙ 2OH​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Iron [II] hydroxide : Fe(OH)2\bold{Fe(OH)_2}Fe(OH)2​(r) Iron [III] sulphideStep 1 — Write each symbol with its valencyFe3+↗S2−\text{Fe}^{3+} \phantom{\nearrow} \text{S}^{2-}Fe3+↗S2−Step 2 — Interchange the valenciesFe23 ↘↙ S2⇒Fe12 ↘↙ S3\overset{\phantom{2}{3}}{\text{Fe}} \space {\searrow}\mathllap{\swarrow} \space \overset{2}{\text{S}} \Rightarrow \underset{\phantom{1}{2}}{\text{Fe}} \space {\searrow}\mathllap{\swarrow} \space \underset{3}{\text{S}} \[0.5em]Fe23 ↘↙ S2⇒12Fe​ ↘↙ 3S​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Iron [III] sulphide : Fe2S3\bold{Fe_2S_3}Fe2​S3​(s) Iron [III] oxideStep 1 — Write each symbol with its valencyFe3+↗O2−\text{Fe}^{3+} \phantom{\nearrow} \text{O}^{2-}Fe3+↗O2−Step 2 — Interchange the valenciesFe23 ↘↙ O2⇒Fe12 ↘↙ O3\overset{\phantom{2}{3}}{\text{Fe}} \space {\searrow}\mathllap{\swarrow} \space \overset{2}{\text{O}} \Rightarrow \underset{\phantom{1}{2}}{\text{Fe}} \space {\searrow}\mathllap{\swarrow} \space \underset{3}{\text{O}} \[0.5em]Fe23 ↘↙ O2⇒12Fe​ ↘↙ 3O​Step 3 — Write the interchanged number & hence the formulaTherefore, we getFormula of Iron [III] oxide : Fe2O3\bold{Fe_2O_3}Fe2​O3​

Question 4

Question 7(a) What is a chemical equation?(b) Why is it necessary to balance a chemical equation?(c) What are the limitations of a chemical equation?

Accepted Answer

(a) A chemical equation is the symbolic representation of a chemical reaction using symbols and formulae of the substances involved in the reaction.(b) It is necessary to balance a chemical equation so as to make the number of atoms of the reactants equal to the number of atoms of the products because a chemical reaction is just a rearrangement of atoms and atoms are neither created nor destroyed during the chemical reaction.(c) The limitations of a chemical equation are:It does not inform about:the physical states of the reactants and the products i.e. whether they are solids, liquids or gases.the concentration of reactants and products.the time taken for the completion of reaction.the rate at which a reaction proceeds.the heat changes during the reaction i.e. whether heat is given out or absorbed.the conditions such as temperature, pressure, catalyst, etc. which affect the reaction.the nature of the reaction i.e. whether it is reversible or irreversible.

Question 5

Question 8What are the ways by which a chemical equation can be made more informative?

Accepted Answer

A chemical equation can be made more informative by the following ways:The physical state of the reactants and products can be indicated by putting s for solid, l for liquid, g for gas, aq. for aqueous state besides the symbols for the reactants and products.Evolution or absorption of heat during the reaction can be denoted by adding or subtracting a heat term on the product side.Temperature, pressure and catalyst can be indicated above the arrow (⟶) separating the reactants and products.Concentration of reactants and products are indicated by adding the words (dil.) for dilute and (conc.) for concentrated before their formulae.By the sign ⟶ or ⇌ information about irreversible and reversible reactions can be known.Upward arrow (↑) indicates a gas is evolved, downward arrow (↓) indicates a precipitate is formed, sign delta (Δ) indicates heat is evolved or absorbed.

Question 6

Question 9State the law of conservation of mass.

Accepted Answer

Law of conservation of mass states that matter can neither be created nor be destroyed, it can only be transformed from one form to another.

Question 7

Question 10Differentiate between:(a) Reactants and Products(b) A balanced and an unbalanced chemical equation

Accepted Answer

(a) Differences between Reactants and ProductsReactantsProductsThe substances that are used as the starting material and which react with one another are called reactants.The substances which are formed as a result of the reaction are called products.Reactants are written on the left hand side of the equation.Products are written on the right hand side of the equation.In equation C + O2 ⟶ CO2, C and O2 are reactants.In equation C + O2 ⟶ CO2, CO2 is product.(b) Differences between a balanced and an unbalanced chemical equationBalanced chemical equationUnbalanced chemical equationIn balanced chemical equation the total number of atoms on the reactant side as well as the product side are equal.In unbalanced chemical equation the total number of atoms on the reactant side and product side are not equal.Example:Zn + H2SO4 ⟶ ZnSO4 + H2Example:H2 + O2 ⟶ H2O

Question 8

Question 11Balance the following equations:N2 + H2 ⟶ NH3H2 + O2 ⟶ H2ONa2O + H2O ⟶ NaOHCO + O2 ⟶ CO2Zn + HCl ⟶ ZnCl2 + H2

Accepted Answer

N2 + 3H2 ⟶ 2NH32H2 + O2 ⟶ 2H2ONa2O + H2O ⟶ 2NaOH2CO + O2 ⟶ 2CO2Zn + 2HCl ⟶ ZnCl2 + H2

Question 9

Question 12Write balanced chemical equations for the following word equations:Iron + Chlorine ⟶ Iron(III) chlorideMagnesium + dil. sulphuric acid ⟶ Magnesium sulphate + hydrogenMagnesium + oxygen ⟶ Magnesium oxideCalcium oxide + water ⟶ Calcium hydroxideSodium + Chlorine ⟶ Sodium chloride

Accepted Answer

2Fe + 3Cl2 ⟶ 2FeCl3Mg + H2SO4 ⟶ MgSO4 + H22Mg + O2 ⟶ 2MgOCaO + H2O ⟶ Ca(OH)22Na + Cl2 ⟶ 2NaCl

Question 10

Question 13What information do you get from the following chemical equation?Zn(s) + 2HCl (dil) ⟶ ZnCl2 (aq) + H2 (g)

Accepted Answer

We get the following information from the given chemical equation:Zinc and Hydrochloric acid are reactants. Zinc is in solid state that reacts with dilute HCl.The reaction is irreversible.The products formed are aqueous solution of zinc chloride and hydrogen gas.The equation is balanced i.e. number of atoms of each element on reactants and products sides are equal.

Question 11

Question 3Match the compounds in List I - 1 to 20 with their correct formulas in List II - A to T.List I      1. Copper [I] sulphide2. Potassium permanganate3. Phosphoric acid4. Copper [I] oxide5. Carbonic acid6. Aluminium sulphide7. Iron [II] oxide8. Iron [III] sulphide9. Iron [II] sulphate10. Sodium zincate11. Nitrous oxide12. Aluminium sulphate13. Magnesium nitride14. Iron [III] sulphate15. Copper [II] oxide16. Iron [III] oxide17. Nitric oxide18. Copper [II] sulphide19. Iron [II] sulphide20. Magnesium nitrateList II      A. KMnO4B. Mg3N2C. Mg(NO3)2D. Al2(SO4)3E. Na2ZnO2F. N2OG. H2CO3H. Al2S3I. NOJ. FeSK. Fe2S3L. H3PO4M. Cu2SN. CuSO. Fe2O3P. FeOQ. FeSO4R. Fe2(SO4)3S. CuOT. Cu2O

Accepted Answer

CompoundsFormulas1. Copper [I] sulphideM. Cu2S2. Potassium permanganateA. KMnO43. Phosphoric acidL. H3PO44. Copper [I] oxideT. Cu2O5. Carbonic acidG. H2CO36. Aluminium sulphideH. Al2S37. Iron [II] oxideP. FeO8. Iron [III] sulphideK. Fe2S39. Iron [II] sulphateQ. FeSO410. Sodium zincateE. Na2ZnO211. Nitrous oxideF. N2O12. Aluminium sulphateD. Al2(SO4)313. Magnesium nitrideB. Mg3N214. Iron [III] sulphateR. Fe2(SO4)315. Copper [II] oxideS. CuO16. Iron [III] oxideO. Fe2O317. Nitric oxideI. NO18. Copper [II] sulphideN. CuS19. Iron [II] sulphideJ. FeS20. Magnesium nitrateC. Mg(NO3)2

Question 12

Question 4Underline the incorrectly balanced compound in each equation & rewrite the correct equation.2Na + 3H2O ⟶ 2NaOH + H24P + 4O2 ⟶ 2P2O5Fe2O3 + 2H2 ⟶ 2Fe + 3H2O2Al + 2H2SO4 ⟶ Al2(SO4)3 + 3H2N2 + 3H2 ⇌ NH3ZnO + 3NaOH ⟶ Na2ZnO2 + H2OFeCl3 + 3NH4OH ⟶ 2NH4Cl + Fe(OH)3FeS + 2HCl ⟶ 2FeCl2 + H2S3NH3 + H2SO4 ⟶ (NH4)2SO4PbO2 + 4HCl ⟶ PbCl2 + H2O + Cl2

Accepted Answer

2Na + 2H2O ⟶ 2NaOH + H24P + 5O2 ⟶ 2P2O5Fe2O3 + 3H2 ⟶ 2Fe + 3H2O2Al + 3H2SO4 ⟶ Al2(SO4)3 + 3H2N2 + 3H2 ⇌ 2NH3ZnO + 2NaOH ⟶ Na2ZnO2 + H2OFeCl3 + 3NH4OH ⟶ 3NH4Cl + Fe(OH)3FeS + 2HCl ⟶ FeCl2 + H2S2NH3 + H2SO4 ⟶ (NH4)2SO4PbO2 + 4HCl ⟶ PbCl2 + 2H2O + Cl2

Question 13

Question 7Differentiate between the terms - 'Ion' & 'radical' with suitable examples.

Accepted Answer

IonRadicalAn ion is any atom or a group of atoms carrying a positive or negative charge due to loss or gain of electrons.A radical is an atom or a group of atoms of the same or of different elements that behaves as a single unit with a positive or a negative charge.Positively charged ions are called cations. For example, Sodium [Na1+]Positively charged radicals are called basic radicals. For example, Ammonium [NH41+]Negatively charged ions are called anions. For example, Chloride [Cl1-].Negatively charged radicals are called acidic radicals. For example, Bicarbonate [HCO31-]

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