Law of Constant Heat Of Enthalpy

Born Haber Cycle MCQ Quiz With Answers

2.

Consider the hypothetical reaction below: Mg(s) + 3/2 Cl2(g) ---------- MgCl3(s) The possible value of the standard enthalpy of formation for magnesium (III) chloride is

-114 KJ/Mol
3841 KJ/Mol
432 KJ/Mol
-432 KJ/Mol

Correct Answer

A. 3841 KJ/Mol

Explanation

The correct answer is 3841 KJ/Mol. The reaction given is the formation of magnesium (III) chloride from its elements. The standard enthalpy of formation is the change in enthalpy when one mole of a compound is formed from its elements in their standard states. In this case, one mole of magnesium (III) chloride is formed from magnesium and chlorine gas. The positive value of 3841 KJ/Mol suggests that the formation of magnesium (III) chloride is an endothermic process, requiring energy to form the compound.

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3.

The lattice energy of rubidium fluoride , RbF and caesium chloride , CsCl are 760KJ/Mol and 650 KJ/Mol respectively. The lattice energy of caesium flouride ,CsF is expected to be,

600 KJ/Mol
720 KJ/Mol
365 KJ/Mol
432 KJ/Mol

Correct Answer

A. 720 KJ/Mol

Explanation

The lattice energy is a measure of the strength of the ionic bond between ions in a crystal lattice. It is directly proportional to the charge of the ions and inversely proportional to the distance between them. In this case, we can compare the lattice energies of RbF and CsCl to predict the lattice energy of CsF. Since CsCl has a lower lattice energy than RbF, it means that the Cs+ ion has a larger size than the Rb+ ion. Since fluoride ion (F-) is the same in both compounds, the larger Cs+ ion will have a stronger attraction to the F- ion, resulting in a higher lattice energy for CsF. Therefore, the expected lattice energy of CsF is 720 KJ/Mol.

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4.

The standard enthalpy of combustion of C is -393 KJ/Mol . Choose the corect value of enthalpy for the reaction 2C(S) + O2(g) ------------2CO2 (g)

-786 KJ/Mol
534 KJ/Mol
786 KJ/Mol
432 KJ/Mol

Correct Answer

A. -786 KJ/Mol

Explanation

The standard enthalpy of combustion of C is -393 KJ/Mol, which means that when one mole of carbon is burned, -393 KJ of energy is released. In the given reaction, two moles of carbon are reacting with one mole of oxygen to form two moles of carbon dioxide. Since the enthalpy change is proportional to the amount of substance involved, the enthalpy change for this reaction would be twice the enthalpy of combustion of carbon. Therefore, the correct value of enthalpy for the reaction 2C(S) + O2(g) -> 2CO2(g) would be -786 KJ/Mol.

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5.

What the mass of methane must be burn to raise 2.00 Kg of water at 20 celcius to 100 celcius ? (Heat capacity of water = 4.18 J/gK , Heat of combustion of methane = -890 KJ/Mol)

120 g
12.0g
1.20g
0.12g

Correct Answer

A. 12.0g

Explanation

To raise the temperature of water from 20°C to 100°C, we need to calculate the amount of heat required. The heat capacity of water is given as 4.18 J/gK, which means it takes 4.18 Joules of energy to raise the temperature of 1 gram of water by 1 Kelvin.

The temperature change is 100°C - 20°C = 80°C = 80 K.

The mass of water is given as 2.00 Kg = 2000 g.

So, the amount of heat required is 4.18 J/gK * 2000 g * 80 K = 668,800 J.

Now, we need to convert this energy value to kilojoules by dividing by 1000: 668,800 J / 1000 = 668.8 KJ.

The heat of combustion of methane is given as -890 KJ/Mol.

To find the mass of methane required, we can set up a proportion:

668.8 KJ / -890 KJ = x g / 1 mol.

Simplifying the proportion, we find that x = (668.8 KJ * 1 mol) / -890 KJ = -0.75 mol.

Since the molar mass of methane is 16 g/mol, the mass of methane required is -0.75 mol * 16 g/mol = -12 g.

However, mass cannot be negative, so the correct answer is 12.0 g.

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6.

The statement below are true about Born-Haber cycle except

The cycle is an application of Hess Law.
It can be used to determine the lattice energy of an ionic solid.
The cycle shows the amount of activation energy involved in a reaction.
All of these

Correct Answer

A. The cycle shows the amount of activation energy involved in a reaction.

Explanation

The Born-Haber cycle is an application of Hess's Law and can be used to determine the lattice energy of an ionic solid. However, it does not show the amount of activation energy involved in a reaction. Activation energy is the energy required to initiate a chemical reaction, while the Born-Haber cycle focuses on the enthalpy changes associated with the formation of an ionic compound. Therefore, the correct answer is "The cycle shows the amount of activation energy involved in a reaction."

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7.

Hess Law is known as

Law of Constant Heat Summation
Law of Constant Heat Of Enthalpy
Law of Constant Heat Capacity
Born-Haber Cycle

Correct Answer

A. Law of Constant Heat Summation

Explanation

Hess's Law states that the total enthalpy change for a chemical reaction is independent of the pathway taken. This means that the overall enthalpy change can be calculated by summing the enthalpy changes of individual steps in a reaction, regardless of the number of intermediate steps or the specific route taken. Therefore, the correct answer is "Law of Constant Heat Summation" as it accurately describes the principle behind Hess's Law.

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8.

Born-Haber Cycle is an energy cycle for

Aqueous solution
Solid compounds
Ionic compounds
Molecular compounds

Correct Answer

A. Ionic compounds

Explanation

The Born-Haber Cycle is an energy cycle used to determine the lattice energy of ionic compounds. It involves a series of steps, including the formation of gaseous ions, the formation of solid compounds, and the formation of the final ionic compound. The cycle allows for the calculation of the lattice energy by considering the enthalpy changes of each step. Therefore, the correct answer is ionic compounds, as the Born-Haber Cycle is specifically designed for this type of compound.

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9.

A measure of the stability of the crystal lattice , given by the energy that would be released per mole if atoms , ions ,or molecules of the crystal were brought together from infinite distances apart to form the lattice is known as

Born -Haber Cycle
Lattice energy
Hess Law
All of these

Correct Answer

A. Lattice energy

Explanation

Lattice energy is a measure of the stability of the crystal lattice. It represents the energy that would be released per mole if the atoms, ions, or molecules of the crystal were brought together from infinite distances apart to form the lattice. This energy is an important factor in determining the overall stability and strength of the crystal structure. Therefore, lattice energy is the correct answer.

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10.

The Born-Haber cycle required the following enthalpies except

Enthalpy of formation
Enthalpy of solution
Electron affinity
Electron deficiency

Correct Answer

A. Enthalpy of solution

Explanation

The Born-Haber cycle is a series of steps used to determine the lattice energy of an ionic compound. It involves various enthalpies, including the enthalpy of formation, electron affinity, and enthalpy of solution. However, the enthalpy of solution is not required in the Born-Haber cycle. This is because the enthalpy of solution refers to the energy change when a solute is dissolved in a solvent, which is not directly related to the lattice energy calculation in the Born-Haber cycle.

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Born Haber Cycle MCQ Quiz With Answers

Which of the following compounds is expected to have the highest lattice energy?

Quiz Preview

Consider the hypothetical reaction below: Mg(s) + 3/2 Cl2(g) ---------- MgCl3(s) The possible value of the standard enthalpy of formation for magnesium (III) chloride is

The lattice energy of rubidium fluoride , RbF and caesium chloride , CsCl are 760KJ/Mol and 650 KJ/Mol respectively. The lattice energy of caesium flouride ,CsF is expected to be,

The standard enthalpy of combustion of C is -393 KJ/Mol . Choose the corect value of enthalpy for the reaction 2C(S) + O2(g) ------------2CO2 (g)

What the mass of methane must be burn to raise 2.00 Kg of water at 20 celcius to 100 celcius ? (Heat capacity of water = 4.18 J/gK , Heat of combustion of methane = -890 KJ/Mol)

The statement below are true about Born-Haber cycle except

Hess Law is known as

Born-Haber Cycle is an energy cycle for

A measure of the stability of the crystal lattice , given by the energy that would be released per mole if atoms , ions ,or molecules of the crystal were brought together from infinite distances apart to form the lattice is known as

The Born-Haber cycle required the following enthalpies except