The destruction of the ozone layer by chlorofluorocarbons (CFC’s) can be described by the following reactions:ClO(g) + O3(g) ? Cl(g) + 2 O2(g) ?H°rxn = –29.90 kJ2 O3(g) ? 3 O2(g) ?H°rxn = 24.18 kJDetermine the value of heat of reaction for the following:Cl(g) + O3(g) ? ClO(g) + O2(g) ?H°=_____________?
Answers
Answer:
ΔH°rxn = 54.08 kJ
Explanation:
Let's consider the following equations.
a) ClO(g) + O₃(g) ⇄ Cl(g) + 2 O₂(g) ΔH°rxn = –29.90 kJ
b) 2 O₃(g) ⇄ 3 O₂(g) ΔH°rxn = 24.18 kJ
We have to determine the value of heat of reaction for the following reaction: Cl(g) + O₃(g) ⇄ ClO(g) + O₂(g)
According to Hess's law, the enthalpy change in a chemical reaction is the same whether the reaction takes place in one or in several steps. That means that we can find the enthalpy of a reaction by adding the corresponding steps and adding their enthalpies. According to Lavoisier-Laplace's law, if we reverse a reaction, we also have to reverse the sign of its enthalpy.
Let's reverse equation a) and add it to equation b).
-a) Cl(g) + 2 O₂(g) ⇄ ClO(g) + O₃(g) ΔH°rxn = 29.90 kJ
b) 2 O₃(g) ⇄ 3 O₂(g) ΔH°rxn = 24.18 kJ
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Cl(g) + 2 O₂(g) + 2 O₃(g) ⇄ ClO(g) + O₃(g) + 3 O₂(g)
Cl(g) + O₃(g) ⇄ ClO(g) +O₂(g)
ΔH°rxn = 29.90 kJ + 24.18 kJ = 54.08 kJ
Final answer:
The heat of the reaction (ΔH°rxn) for the reaction Cl(g) + O3(g) ? ClO(g) + O2(g) is calculated using Hess's Law. The sum of the heat of reversed first reaction and the second reaction provided is 54.08 kJ.
Explanation:
The chemistry question asks to determine the heat of the reaction for the reaction Cl(g) + O3(g) ? ClO(g) + O2(g). In Hess's Law, the heat of the reaction or ΔH for a reaction can be calculated from the sum of the heats of other reactions that sum to the desired reaction. In this case, we want to reverse the first reaction provided (which changes the sign of ΔH) and add it to the second reaction provided.
So, reversing the first reaction we get: Cl(g) + 2 O2(g) ? ClO(g) + O3(g) ?H°rxn = 29.90 kJ
Adding this to the second reaction: 2 O3(g) ? 3 O2(g), ?H°rxn = 24.18 kJ, gives the reaction Cl(g) + O3(g) ? ClO(g) + O2(g). Adding the ΔH values gives the ΔH for this reaction: 29.90 kJ + 24.18 kJ = 54.08 kJ. So, ?H°rxn for the reaction Cl(g) + O3(g) ? ClO(g) + O2(g) is 54.08 kJ.
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A reaction mixture initially contains a Br2 partial pressure of 751 torr and a Cl2 partial pressure of 737 torr at 150 K.
Calculate the equilibrium partial pressure of BrCl.
Answers
Answer:
the equilibrium partial pressure of BrCl is pBC = 784.52 torr
Explanation:
Since
Br₂(g) + Cl₂(g) ⇌ 2BrCl(g) , Kp=1.112 at 150 K
denoting BC as BrCl , B as Br₂ , C as Cl₂, p as partial pressure , then
Kp = pBC²/[pB*pC]
solving for pBC
pBC = √(Kp*pB*pC)
replacing values
pBC = √(Kp*pB*pC) = √(1.112*751 torr*737 torr) = 784.52 torr
pBC = 784.52 torr
then the equilibrium partial pressure of BrCl is pBC = 784.52 torr
Final answer:
To calculate the equilibrium partial pressure of BrCl, use the equilibrium constant expression and substitute the given partial pressures of Br2 and Cl2. The equilibrium partial pressure of BrCl is approximately 0.0375 atm.
Explanation:
To calculate the equilibrium partial pressure of BrCl, we need to use the equilibrium constant expression:
Kp = ([BrCl]^2) / ([Br2] * [Cl2])
Given that the equilibrium partial pressures of Br2 and Cl2 are 0.450 atm and 0.115 atm, respectively, we can substitute these values into the expression:
1.112 = ([BrCl]^2) / (0.450 * 0.115)
Simplifying the expression, we find that the equilibrium partial pressure of BrCl is approximately 0.0375 atm.
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b. Negative
c. Zero
d. Impossible to determine
Answers
Answer: The standard free energy change for a reaction in an electrolytic cell is always positive.
Explanation:
Electrolytic cells use electric currents to drive a non-spontaneous reaction forward.
Relation of standard free energy change and emf of cell
where,
= standard free energy change
n= no of electrons gained or lost
F= faraday's constant
= standard emf
= standard emf = -ve , for non spontaneous reaction
Thus
Thus standard free energy change for a reaction in an electrolytic cell is always positive.
HBr
H2O
HI
Answers
Explanation:
It is known that acidic strength of hydrides of same group tends to increase when we move from top to bottom in a group. On the other hand, acidic strength of hydrides of same period elements increases when we move from left to right in a period.
As both bromine and iodine belongs to the same group. Also, selenium and oxygen are same group elements. Therefore, their acidic strength increases on moving down the group.
Therefore, we can conclude that acidic strength of given compounds from strongest to weakest is as follows.
HI > HBr > >
Final answer:
To rank the acids in decreasing acid strength using periodic trends, consider the size, electronegativity, and presence of lone pairs of electrons. HI is the strongest acid, followed by HBr, H2O, and H2Se.
Explanation:
To rank the acids in order of decreasing acid strength using periodic trends, we need to consider the size and electronegativity of the atoms. The larger the atom, the weaker the acid, and the more electronegative the atom, the stronger the acid. Additionally, we can consider the presence of lone pairs of electrons, as they increase the acidity.
- HI - Iodine (I) is larger and less electronegative than the other halogens. It also has a lone pair of electrons, making it the strongest acid.
- HBr - Bromine (Br) is larger and less electronegative than chlorine (Cl), and it also has a lone pair of electrons. It is the second strongest acid.
- H2O - Oxygen (O) is smaller and more electronegative than the halogens. It does not have a lone pair of electrons, making it a weaker acid than the halogens.
- H2Se - Selenium (Se) is larger and less electronegative than sulfur (S). However, it does not have a lone pair of electrons, making it the weakest acid.
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Answers
Answer:
c. an element.
Explanation:
An element -
It refers to the substance , which has same type of atoms , with exactly same number of protons , is referred to as an element .
In term of chemical species , elements are the smallest one , and can not be bifurcated down to any further small substance by the means of any chemical reaction .
Hence , from the given information of the question ,
The correct term is an element .
Answer:
C. an element.
Explanation:
Answers
According to the valence bond theory the triple bond in ethyne consists of one sigma bond and two pi bonds.
Explanation:
Atomic number of carbon is 6. The ground state electronic configuration of carbon is as follow,
1s², 2s², 2p²
And the excited state electronic configuration of carbon is as follow,
1s², 2s¹, 2px¹, 2py¹, 2pz¹
In ethyne the 2s¹ orbital and 2px¹ orbitals having unpaired electrons form sigma bonds by head to head overlapping with orbitals of hydrogen atom and carbon atom. The remaining 2py¹ and 2pz¹ orbitals of both carbons overlap perpendicular to the existing sigma bond resulting in the formation of two pi bonds.
slow down and move closer together.
merge together to form fewer atoms.
speed up and move further apart.