Answer:
-125 kJ
Explanation:
You calculate the energy required to break all the bonds in the reactants. Then you subtract the energy to break all the bonds in the products.
H₂C=CH₂ + H₂ ⟶ H₃C-CH₃
Bonds: 4C-H + 1C=C 1H-H 6C-H + 1C-C
D/kJ·mol⁻¹: 413 612 436 413 347
The formula relating ΔHrxn and bond dissociation energies (D) is
ΔHrxn = Σ(Dreactants) – Σ(Dproducts)
(Note: This is an exception to the rule. All other thermochemical reactions are “products – reactants”. With bond energies, it’s “reactants – products”. The reason comes from the way we define bond energies.)
<em>For the reactant</em>s:
Σ(Dreactants) = 4 × 413 + 1 × 612 + 1 × 436 = 2700 kJ
<em>For the products:</em>
Σ(Dproducts) = 6 × 413 + 1 × 347 = 2825 kJ
<em>For the system</em>
:
ΔHrxn = 2700 - 2825 = -125 kJ
Answer:
D. Nuclei with small masses combine to form nuclei with larger masses.
B. A small amount of mass in the nuclei that combine is converted to energy
Explanation:
A nuclear fusion, in contrary to fission, is the process by which the nuclei of two atoms combine to form a much larger atom with a large nuclei. Likewise, during a fusion reaction, a large amount of energy is released from the small amount of mass in the nuclei (two) that combines.
According to this question, the following are true of a fusion reaction:
- Nuclei with small masses combine to form nuclei with larger masses.
- A small amount of mass in the nuclei that combine is converted to enormous energy.
Answer:
Lewis structure for nitrogen triiodide,
is given in the attachment.
Explanation:
Given:
The given compound is Nitrogen triiodide. In which 1 atom of Nitrogen combines with 3 atoms of Iodine. Both Nitrogen and Iodine are non-metals,So they form covalent bond by sharing of electrons.
The electron configuration of Nitrogen and Iodine is given below;
There are 5 electrons in valance shell of Nitrogen atom and 7 electrons in valance shell of Iodine atom.
So, 3 atom of Iodine shares 1 electron with 1 electrons of Nitrogen.
The Lewis dot Structure is in the attachment.
Answer:
doublet
Explanation:
Proton MNR is used for the determination of no. of equivalents protons in a molecule
In the molecule, single NMR signal is produced for each set of protons.
Signal splitting is called spin-spin coupling and the splitting of signals depends upon the no. of neighboring proton.
The no. of signal for a proton is equal to n+1, where n is neighboring protons.
In 1-bromo-2-methylpropane, neighboring proton for both methyl protons are one. But the chemical environment of both the methyl protons are different.
Neighboring proton for methyl protons = 1
No. of signal for methyl protons = 1+1 =2
Hence, two doublets will be generated for each set of methyl protons. protons.
Answer:
5.5 moles of given substance.
Explanation:
The given problem can be solved by using the Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
Solution:
3.311 ×10²⁵ / 6.022 × 10²³ = moles
5.5 moles of given substance.
