Given data:
Sublimation of K
K(s) ↔ K(g) ΔH(sub) = 89.0 kj/mol
Ionization energy for K
K(s) → K⁺ + e⁻ IE(K) = 419 Kj/mol
Electron affinity for Cl
Cl(g) + e⁻ → Cl⁻ EA(Cl) = -349 kj/mol
Bond energy for Cl₂
1/2Cl₂ (g) → Cl Bond energy = 243/2 = 121.5 kj/mol
Formation of KCl
K(s) + 1/2Cl₂(g) → KCl(s) ΔHf = -436.5 kJ/mol
To determine:
Lattice energy of KCl
K⁺(g) + Cl⁻(g) → KCl (s) U(KCl) = ?
Explanation:
The enthalpy of formation of KCl can be expressed in terms of the sum of all the above processes, i.e.
ΔHf(KCl) = U(KCl) + ΔH(sub) + IE(K) + 1/2 BE(Cl₂) + EA(Cl)
therefore:
U(KCl) = ΔHf(KCl) - [ΔH(sub) + IE(K) + 1/2 BE(Cl₂) + EA(Cl)]
= -436.5 - [89 + 419 + 243/2 -349] = -717 kJ/mol
Ans: the lattice energy of KCl = -717 kj/mol
The lattice energy of KCl is calculated using the Born-Haber cycle by considering the energies of several steps including the sublimation of potassium, ionization of potassium, dissociation of Cl bond, electron affinity of Cl, and formation of KCl. The given values are plugged into a formula resulting in a lattice energy of -718 kJ/mol.
To calculate the lattice energy of KCl using the Born-Haber cycle, we need to follow several thermochemical steps. The steps include, first sublimation of potassium, the ionization of potassium, bond dissociation enthalpy to produce Cl, the electron affinity of Cl, and formation of KCl (s). Combining energy changes associated with all these steps would give us energy change for the formation of KCl from individual K and Cl2, it is called as enthalpy of formation (ΔH°f) for KCl.
Using the given values for each step, we use the formula: ΔH°f = ΔHsub + IE1 + 1/2* DCl2 - EA1 + lattice energy.
Substituting the given values, -436.5 = 89 + 419 + 1/2*243 -349 + lattice energy. Solving gives the lattice energy as -718 kJ/mol.
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Explanation: apex 1/10/2020
Answer: 7.6 g of water are required to make 12.6 g of glucose
Explanation:
Moles is calculated by using the formula:
The balanced chemical equation is:
According to stoichiometry:
1 mole of glucose is produced by = 6 moles of water
Thus 0.07 moles of glucose is produced by = moles of water
Mass of water required =
Thus 7.6 g of water are required to make 12.6 g of glucose
The addition of a proton to the sulfur atom has resulted in the formation of an isotope. Thus, option A is correct.
The addition of a proton to the nucleus has been resulted in the change in the atomic mass of the element without changing the atomic number.
The atomic mass has been the number of protons and neutrons present in the nucleus. The ions have been resulted when there has been a change in the number of electrons in the atom.
The isotopes have been the element that has been considered of the same atomic number with different atomic masses. The addition of a proton to the sulfur atom changes its atomic mass and thereby forms the isotope of sulfur. Thus, option A is correct.
For more information about the protons and electrons, refer to the link:
Answer:
Created a positively charged ion of Sulfur
Explanation:
As the number of protons in Sulfur is more than the electrons in Sulfur, thus it'll be a positively charged ion of Sulfur
sodium (Na) and potassium (K)
carbon (C) and oxygen (O)
boron (B) and beryllium (Be)
Answer:
The correct answer is the second option; sodium (Na) and potassium (K.)
Both sodium and potassium have the same number of valence electrons.
Explanation:
b. False
the answer is false cause i tried true first and got it wrong.
Answer:
False
Explanation:
Not all solids have an orderly internal structure, although some do which are called crystalline solids. Some examples are metals and table salt. Solids without a orderly internal structure are called amorphous solids. Examples of this are glass, plastics, and rubber.
B) Drug
C) Medicine
D) Screening Tool
Ohp xD nvm, the answer is A !
During the test trial, the sugar pill given to the control group is called a placebo. Therefore, the correct option is A. Placebo
A placebo is any drug or a treatment with no active substances, for example a sugar pill.
During clinical trials, usually one group takes the actual drug while the other group takes the placebo without being aware of it.
Placebo is an inactive treatment given to a group of people that is made to look like the real drug, but in reality it simply makes the patient believe they're being treated with the drug and that the drug will help them relieve from the symptoms.
By comparing the results from the two groups, this method helps in analyzing the accurate effects of the drug on the patients and helps in proving that it was the drug that actually treated the symptom and that the treatment did not occur by chance or just a mere belief of the patient thinking they will get better because they're being treated.
This approach helps reduce bias and ensures that the trial's results are more accurate and reliable.
So, the sugar pill given to the control group is called a placebo. Therefore, the correct option is A. Placebo
To learn more about placebo, click on
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