Born Haber Cycle MCQ Quiz With Answers

Explanation
MgF2 is expected to have the highest lattice energy because it has the highest charge and the smallest ionic radius among the given compounds. Lattice energy is directly proportional to the charge of the ions and inversely proportional to the distance between them. Since MgF2 has a 2+ charge on the Mg ion and a 1- charge on the F ion, the electrostatic attraction between them is stronger than in the other compounds. Additionally, the small ionic radius of Mg2+ and the small ionic radius of F- result in a shorter distance between the ions, further increasing the lattice energy.

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.

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.

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.

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.

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."

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.

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.

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.

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.