Calculate the lattice energy of potassium oxide from the following data:

Question

Calculate the lattice energy of potassium oxide from the following data:

Enthalpy of sublimation of potassium: +89.24 kJ/mol
Bond energy of oxygen: +498 kJ/mol
First ionization energy of potassium: +419 kJ/mol
1st electron affinity of oxygen: -141 kJ/mol
2nd electron affinity of oxygen: +744 kJ/mol
deltaHf potassium oxide: −363.17 kJ/mol

the answer is - 2232 kJ/mol. i do not know how to go about getting this answer. i know youre supposed to add everything and have it equal -363.17 but i don't know if there is something that i should exclude or something that i'm supposed to multiply by two. i just really need help please

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5 answers
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Answer 1

Henry answered
8 years ago

2K(s) + 1/2O2(g)---->K2O deltaH=−363.17 kJ or better still,

K2O --->2K(s) + 1/2O2(g)deltaH=363.17
take note that the equation is reversed above.
2K(s)---->2K(g) deltaH=2(+89.24 kJ/mol )=178.48kJ
2K(g)---->2K+(g) deltaH=2(+419 kJ/mol )=838kJ
1/2O2(g)---->O(g) deltaH=1/2(498 kJ/mol )=249kJ
O(g)---->O-(g) deltaH=-141kJ
O-(g)---->O2-(g) deltaH=744
as such, from the energy cycle (Born Haber cycle for K2O, the LE=-(363.17+178.48+838+249-141+744)=2231.65~2232kJ/mol

Answer 2

Henry Wosor answered
8 years ago

2K(s) + 1/2O2(g)---->K2O deltaH=−363.17 kJ or better still,

K2O --->2K(s) + 1/2O2(g)deltaH=363.17
take note that the equation is reversed above.
2K(s)---->2K(g) deltaH=2(+89.24 kJ/mol )=178.48kJ
2K(g)---->2K+(g) deltaH=2(+419 kJ/mol )=838kJ
1/2O2(g)---->O(g) deltaH=1/2(498 kJ/mol )=249kJ
O(g)---->O-(g) deltaH=-141kJ
O-(g)---->O2-(g) deltaH=744
as such, from the energy cycle (Born Haber cycle for K2O, the LE=-(363.17+178.48+838+249-141+744)=-2231.65~-2232kJ/mol

Answer 3

Clown Bot answered
1 year ago

Well, it seems like you're in quite a pickle there. Don't worry, I've got a formula that might help you out. To calculate the lattice energy, you can use the following equation:

Lattice Energy = (Enthalpy of Sublimation of Potassium + Bond Energy of Oxygen + First Ionization Energy of Potassium + Second Electron Affinity of Oxygen) - (DeltaHf Potassium Oxide + First Electron Affinity of Oxygen)

Now, let's plug in the values you've provided:

Lattice Energy = (+89.24 kJ/mol + 498 kJ/mol + 419 kJ/mol + 744 kJ/mol) - (-363.17 kJ/mol + (-141 kJ/mol))

Simplifying this equation, we get:

Lattice Energy = 2350.24 kJ/mol - (-504.17 kJ/mol)

Lattice Energy = 2350.24 kJ/mol + 504.17 kJ/mol

Lattice Energy = 2854.41 kJ/mol

So, according to my calculations, the lattice energy of potassium oxide is approximately 2854.41 kJ/mol. I'm sorry to burst your bubble, but it looks like your answer is not -2232 kJ/mol. Better luck next time!

Answer 4

Step-by-Step Bot answered
11 months ago

To calculate the lattice energy of potassium oxide, you can use the Born-Haber cycle, which involves a series of steps. Here's how you can approach it:

Step 1: Write the balanced equation for the formation of potassium oxide:
2K(s) + 1/2O2(g) -> K2O(s)

Step 2: Calculate the sublimation energy of potassium. This is the energy required to convert one mole of solid potassium (K) into gaseous potassium atoms (K(g)).
ΔH(sub) = +89.24 kJ/mol

Step 3: Calculate the ionization energy of potassium. This is the energy required to remove one electron from a mole of potassium atoms (K(g)).
ΔH(ion) = +419 kJ/mol

Step 4: Calculate the electron affinity of oxygen. This is the energy released when one mole of oxygen atoms (O(g)) gains an electron.
ΔH(ea) = -141 kJ/mol

Step 5: Calculate the lattice energy of potassium oxide (K2O). This is the energy released when one mole of potassium ions (K+) and one mole of oxide ions (O2-) combine to form one mole of solid potassium oxide (K2O(s)).
ΔH(latt) = ?

The lattice energy can be calculated using the following equation:
ΔH(latt) = ΔH(f) + ΔH(sub) + 1/2ΔH(ion) + ΔH(ea)

Since we're calculating the lattice energy using the formation enthalpy (ΔH(f)) of potassium oxide, which is -363.17 kJ/mol, we have:
ΔH(latt) = -363.17 kJ/mol + 89.24 kJ/mol + (1/2)(419 kJ/mol) + (-141 kJ/mol)

Evaluating this equation, we get:
ΔH(latt) = -363.17 + 89.24 + 209.5 - 141
ΔH(latt) = -206.43 kJ/mol

Note: The answer you provided (-2232 kJ/mol) seems to be incorrect. Double-check your calculations and ensure you're using the correct values for each enthalpy. The correct answer should be -206.43 kJ/mol.

Answer 5

Explain Bot answered
11 months ago

To calculate the lattice energy of potassium oxide (K2O), we can use the Born-Haber cycle. The lattice energy is the energy released when gaseous ions come together to form a solid ionic compound. Here's how to calculate it step by step:

Step 1: Write the formation reaction of potassium oxide.
The formation reaction of K2O can be written as:
2K(s) + 1/2O2(g) -> K2O(s)

Step 2: Break down the formation reaction into several steps.
a) Sublimation of solid potassium:
K(s) -> K(g) (This requires the enthalpy of sublimation of potassium, which is +89.24 kJ/mol)

b) Atomization of oxygen gas:
1/2O2(g) -> O(g) (This is half the bond energy of oxygen, which is +498 kJ/mol)

c) Ionization of potassium atoms:
K(g) -> K+(g) + e- (This requires the first ionization energy of potassium, which is +419 kJ/mol)

d) Electron affinity of oxygen:
O(g) + e- -> O-(g) (This is the first electron affinity of oxygen, which is -141 kJ/mol)

e) Formation of potassium oxide lattice:
K+(g) + O-(g) -> K2O(s) (This is the lattice energy we want to calculate)

Step 3: Apply Hess's law to sum up the energies.
According to Hess's law, the sum of energies in a cycle should be equal to zero. Therefore, we can set up the equation:
ΔHf(K2O) = ΔHsub(K) + 1/2ΔHbond(O2) + ΔHion(K) + ΔHea(O) + ΔHlattice(K2O)

Substituting the given values:
-363.17 kJ/mol = +89.24 kJ/mol + 1/2(+498 kJ/mol) + (+419 kJ/mol) + (-141 kJ/mol) + ΔHlattice(K2O)

Step 4: Solve for ΔHlattice(K2O).
ΔHlattice(K2O) = -363.17 kJ/mol - [89.24 kJ/mol + 1/2(498 kJ/mol) + 419 kJ/mol - 141 kJ/mol]
ΔHlattice(K2O) = -363.17 kJ/mol - [(89.24 + 249 + 419 - 141) kJ/mol]
ΔHlattice(K2O) = -363.17 kJ/mol - (616 kJ/mol)
ΔHlattice(K2O) = -979.17 kJ/mol

Note: The negative sign indicates that energy is released during the formation of K2O.

The lattice energy of potassium oxide is approximately -979.17 kJ/mol or -979 kJ/mol in rounded form. The value you mentioned (-2232 kJ/mol) seems to be incorrect. Please verify your calculations or double-check the given values.