Answer:
A
Explanation:
I am very good in science (please give brainliest)
∆H° of the following reaction H₂(g) + I₂(g) → 2HI(g) is -3kJ/mol.
<h3>What is Bond Enthalpy? </h3>
The minimum amount of energy which is required to braak down or form the bonds in chemical reaction is known as bond enthalpy.
It can be calculated as:
∆Hrxn = sum of ∆H bond broken - sum. of ∆H of bond formed.
In order to Calculate ∆Hrxn for the given equation we have:
Bond energies in kJ/mol
- H—H = 436
- H—I = 295
- I—I = 151
Now, the given reaction is
H₂(g) + I₂(g) → 2HI(g)
Here, 1 mol of H₂ and 1 mole of I₂ breaks to form 2 moles of HI.
Therefore,
We know that,
∆Hrxn = B. E(H—H) + B. E(I—I) - 2B. E(H—I)
= 436 + 151 - 2× 295
= 436+ 151 - 590
∆Hrxn = -3kJ/mol.
Thus, from the above conclusion we can say that ∆Hrxn of the reaction H₂(g) + I₂(g) → 2HI(g) is -3kJ/mol.
learn more about Bond energy:
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Answer:
A = The central core and is composed of protons and neutrons.
Explanation:
An atom consist of electrons, protons and neutrons. The neutrons and protons are present inside the nucleus, which is central core of atom and have positive charge. While electron is present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons.
The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.
Symbol= e-
Mass= 9.10938356×10-31 Kg
It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.
While neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.
Symbol of proton= P+
Symbol of neutron= n0
Mass of proton=1.672623×10-27 Kg
Mass of neutron=1.674929×10-27 Kg
Answer:
The option your looking for is letter B: A limiting reactant.
For this problem we can use half-life formula and radioactive decay formula.
Half-life formula,
t1/2 = ln 2 / λ
where, t1/2 is half-life and λ is radioactive decay constant.
t1/2 = 8.04 days
Hence,
8.04 days = ln 2 / λ
λ = ln 2 / 8.04 days
Radioactive decay law,
Nt = No e∧(-λt)
where, Nt is amount of compound at t time, No is amount of compound at t = 0 time, t is time taken to decay and λ is radioactive decay constant.
Nt = ?
No = 1.53 mg
λ = ln 2 / 8.04 days = 0.693 / 8.04 days
t = 13.0 days
By substituting,
Nt = 1.53 mg e∧((-0.693/8.04 days) x 13.0 days))
Nt = 0.4989 mg = 0.0.499 mg
Hence, mass of remaining sample after 13.0 days = 0.499 mg
The answer is "e"