Mole Concept in Balanced Reaction

Q.

Find the total percentage of oxygen in magnesium nitrate crystal Mg(NO₃)₂·6H₂O.
[H = 1, N = 14, O = 16, Mg = 24]

Q.

Nitrogen and oxygen gas react as illustrated by the equation given below:
N₂ (g) + O₂ (g) → 2NO
Calculate the volume of each reacting gas required to produce 1400 cm³ of nitric oxide.

Q. The amount of carbon dioxide produced when 40 g of methane reacts with 48 g of oxygen is.

1. 44 g
2. 33 g
3. 57 g

Q.

Calculate the percentage composition of oxygen in lead nitrate [Pb(NO₃)₂].
(Pb = 207, N = 14, O = 16)

Q. Given below is a balanced chemical reaction for the formation of ammonia.

$N_2\left(g\right)+3H_2\left(g\right)\leftrightharpoons 2N{H}_3\left(g\right)$

Estimate the volume of hydrogen gas required to produce 44.8 litres of $N{H}_3$. (Assume the reaction takes place at STP)

1. 44.8 L
2. 11.2 L
3. 22.4 L
4. 67.2 L

Q.

Which of these chemical equations is not balanced?

1. $2\text{Mg (s)}+{\text{O}}_2\text{(g)}\to 2\text{MgO (s)}$

2. ${\text{CO}}_2\text{(g)}+6{\text{H}}_2\text{O (l)}\to {\text{C}}_6{\text{H}}_{12}{\text{O}}_6\text{(s)}+6{\text{O}}_2\text{(g)}$

3. ${\text{CuCl}}_2\text{(aq)}+{\text{Pb (NO}}_3{)}_2\text{(aq)}\to {\text{Cu(NO}}_3{)}_2\text{(aq)}+{\text{PbCl}}_2\text{(g)}$

4. ${\text{CaCO}}_3\text{(s)}\to \text{CaO (s)}+{\text{CO}}_2\text{(g)}$

Q.

Calculate the percentage of nitrogen and oxygen in ammonium nitrate.

[Relative molecular mass of ammonium nitrate is 80, H = 1, N= 14, 0= 16],

1. 35% Nitrogen, 65% Oxygen

2. 40% Nitrogen, 60% Oxygen

3. 35% Nitrogen, 60% Oxygen

4. 45% Nitrogen, 45% Oxygen

5. 45% Nitrogen, 55% Oxygen

6. 40% Nitrogen, 65% Oxygen

Q.

(a) Calcium carbide is used for the artificial ripening of fruits. Actually the fruit ripens because of the heat evolved while calcium carbide reacts with moisture. During this reaction calcium hydroxide and acetylene gas is formed. If 200 cm³ of acetylene is formed from a certain mass of calcium carbide, find the volume of oxygen required and carbon dioxide formed during the complete combustion. The combustion reaction can be represented as below:
2C₂H_2(g) + 5O_2(g) → 4CO_2(g) + 2H₂O_(g)

(b) A gaseous compound of nitrogen and hydrogen contains 12.5% hydrogen by mass. Find the molecular formula of the compound if its relative molecular mass is 37.
[N = 14, H = 1].

Q. Which of the following chemical equation satisfies the law of conservation of mass?

1. $2C+O_2\to C{O}_2$
2. $C+O_2\to C{O}_2$
3. $4C+O_2\to C{O}_2$
4. $C+2O_2\to C{O}_2$

Q.

From the balanced equation ${\mathrm{CH}}_4+2{\mathrm{O}}_2\to {\mathrm{CO}}_2+2{\mathrm{H}}_2\mathrm{O}$, compute the mass of Oxygen combined with $8\mathrm{g}$ of methane.

Q.

Hydrogen and oxygen combine in a ratio of 1:8 by mass to form water. What mass of oxygen gas is required to react completely with 3g of hydrogen gas?

Q.

(i) LPG stands for liquefied petroleum gas. Varieties of LPG are marketed including a mixture of propane (60%) and butane (40%). If 10 litre of this mixture is burnt, find the total volume of carbon dioxide gas added to the atmosphere. Combustion reactions can be represented as:
C₃H_g(g) + 5O_2(g) → 3CO_2(g) + 4H₂O_(g)
2C₄H_10(g) + 13O_2(g) → 8CO_2(g) + 10H₂O_(g)

(ii) Calculate the percentage of nitrogen and oxygen in ammonium nitrate [Relative molecular mass of ammonium nitrate is 80, H = 1, N = 14, O = 16].

Q.

Hydrogen and oxygen combine in a ratio of 1:8 by mass to form water. What mass of oxygen gas is required to react completely with 3g of hydrogen gas?

1. 16 g

2. 8 g

3. 24 g

4. 32 g

Q.

(i) Calculate the volume of 320 g of SO₂ at stp (Atomic mass: S = 32 and O = 16)
(ii) State Gay-Lussac's Law of combining volumes.
(iii) Calculate the volume of oxygen required for the complete combustion of 8.8 g of propane (C₃H₈). (Atomic mass: C = 14, O = 16, H = 1, Molar Volume = 22.4 dm³ at stp)

Q.

100 sq cm of water gas is exploded with 100sq cm of oxygen and the residual gases are cooled to room temperature . Find the volume composition of the resulting mixture.

Q.

What is meant by a skeletal chemical equation ? Using suitable chemical reaction, differentiate between a skeletal chemical equation and balanced chemical equation

Q.

From the equation.:

C + 2H₂SO₄ → CO₂ + 2H₂O +2SO₂

Calculate:

The volume of sulphur dioxide measured at STP, liberated at the same time.

(Volume occupied by 1 mole of a gas at STP is 224 dm³)

1. 10.7 dm³

2. 10.2 dm³

3. 12.7 dm³

4. 11.7 dm³

5. 12.5 dm³

6. 11.2 dm³

Q.

The equations given below relate to the manufacture of sodium carbonate (Molecular weight of Na₂CO₃ = 106).
NaCl + NH₃ + CO₂ + H₂O $\stackrel{}{\to }$ NaHCO₃ + NH₄Cl
2NaHCO₃ $\stackrel{}{\to }$ Na₂CO₃ + H₂O + CO₂
Questions (a) and (b) are based on the production of 21.2 g of sodium carbonate.
(a) What mass of sodium hydrogen carbonate must be heated to give 21.2 g of sodium carbonate (Molecular weight of NaHCO₃ = 84)?
(b) To produce the mass of sodium hydrogen carbonate, calculate what volume of carbon dioxide, measured at STP would be required?

Q.

10 g NaCl solution is mixed with 17 g of silver nitrate solution. Calculate the weight of silver chloride precipitated.
AgNO₃ + NaCl $\stackrel{}{\to }$ AgCl + NaNO₃ [Ag = 108]

Q.

A sample of ammonium nitrate when heated yields 8.96 litres of steam (measured at STP)
NH₄NO₃ $\stackrel{}{\to }$ N₂O + 2H₂O
(i) What volume of dinitrogen oxide is produced at the same time as 8.96 litres of steam?
(ii) What mass of ammonium nitrate should be heated to produce 8.96 litres of steam?
(Relative molecular mass of ammonium nitrate is 80.)
(iii) Determine the percentage of oxygen in the ammonium nitrate. (O = 16)

Q.

Calculate the volume of air at STP, required to convert 300 mL of sulphur dioxide to sulphur trioxide. Air contains 21% oxygen by volume.

Q. Given below is a balanced chemical reaction for the formation of ammonia.

$N_2\left(g\right)+3H_2\left(g\right)\leftrightharpoons 2N{H}_3\left(g\right)$

Estimate the volume of hydrogen gas required to produce 44.8 litres of $N{H}_3$. (Assume the reaction takes place at STP)

1. 22.4 L
2. 67.2 L
3. 44.8 L
4. 11.2 L

Q.

(a) What volume of hydrogen sulphide at STP will burn in oxygen to yield 12.8 g sulphur dioxide according to the equation?
2H₂S + 3O₂ $\stackrel{}{\to }$ 2H₂O + 2SO₂
(H = 1, O = 16, S = 32)
(b) For the volume of hydrogen sulphide determined in (a) above, what volume of oxygen would be required for complete combustion?

Q.

Balance the chemical equation in a stepwise manner-

$N_2+O_2\underset{}{\to }$$NO$

Q.

What volume of oxygen would be required for complete combustion of 100 litres of ethane according to the following equation?
2C₂H₆ + 7O₂ $\stackrel{}{\to }$ 4CO₂ + 6H₂O

Q.

(a) What volume of oxygen is required to burn completely a mixture of 22.4 dm³ of methane and 11.2 dm³ of hydrogen into carbon dioxide and steam? Equations of the reactions are given below:
CH₄ + 2O₂ $\stackrel{}{\to }$ CO₂ + 2H₂O
2H₂ + O₂ $\stackrel{}{\to }$ 2H₂O
(Assume that all volumes are measured at STP)

(b) The gases hydrogen, oxygen, carbon dioxide, sulphur dioxide and chlorine are arranged in order of their increasing relative molecular mass. Given 8 g of each gas at STP, which gas will contain the least number of molecules and which gas the most?

Q.

What volume of oxygen is required to burn completely a mixture of 22.4 dm³ of methane and 11.2 dm³ of hydrogen into carbon dioxide and steam?

Equations of the reactions are given below. (Assume that all volumes are measured at STP).

CH₄ + 2O₂ → CO₂ +2H₂O

2H₂ + O₂ → 2H₂O

1. 2 vol of CO₂

2. 3 vol of CO₂

3. 4 vol of CO₂

4. 5 vol of CO₂

5. 1 vol of CO₂

Q.

(a) Calculate the percentage of sodium in sodium aluminium fluoride (Na₃AIF₆) correct to the nearest whole number. (F = 19; Na = 23; Al = 27)
(b) 560 ml of carbon monoxide is mixed with 500 ml of oxygen and ignited. The chemical equation for the reaction is as follows:
2CO + O₂ $\stackrel{}{\to }$ 2CO₂
Calculate the volume of oxygen used and carbon dioxide formed in the above reaction.

Q.

(a) A flask contains 3.2 g of sulphur dioxide. Calculate the following:
(i) The moles of sulphur dioxide present in the flask.
(ii) The number of molecules of sulphur dioxide present in the flask.
(iii) The volume occupied by 3.2 g of sulphur dioxide at STP. (S = 32, O = 16)

(b) The reaction of potassium permanganate (VII) with acidified iron (II) sulphate is given below:
2KMnO₄ + 10FeSO₄ + 8H₂SO₄ $\stackrel{}{\to }$ K₂SO₄ + 2MnSO₄ + 5Fe₂(SO₄)₃ + 8H₂O
If 15.8 g of potassium permanganate (VII) was used in the reaction, calculate the mass of iron (II) sulphate used in the above reaction. (K = 39, Mn = 55, Fe = 56, S = 32, O = 16)

Q.

The equation for the burning of octane is:

2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O

What volume, at STP, is occupied by 8 moles of carbon dioxide ?

1. 180.2

2. 170.1

3. 190.1

4. 195

5. 179.2

6. 165