Answer:
One: <u>Selenium</u> is Paramagnetic
Explanation:
Those compounds which have unpaired electrons are attracted towards magnet. This property is called as paramagnetism. Lets see why remaining are not paramagnetic.
Electronic configuration of Scandium;
Sc = 21 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹
Sc³⁺ = 1s², 2s², 2p⁶, 3s², 3p⁶
Hence in Sc³⁺ there is no unpaired electron.
Electronic configuration of Bromine;
Br = 35 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁵
Br⁻ = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶
Hence in Br⁻ there is no unpaired electron.
Electronic configuration of Magnesium;
Mg = 12 = 1s², 2s², 2p⁶, 3s²
Mg²⁺ = 1s², 2s², 2p⁶
Hence in Mg²⁺ there is no unpaired electron.
Electronic configuration of selenium;
Se = 34 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴
Or,
Se = 34 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4px², 4py¹, 4pz¹
Hence in Se there are two unpaired electrons hence it is paramagnetic in nature.
If it is shown as ∆H , then it means that a specific chemical reaction is undergoing heat in Kelvin(K). If it is shown as ∆H° , then it means that a specific chemical reaction is undergoing heat in Celsius(C⁰).
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Answer:
7.7 normility and pH
Explanation:
Trust me im an 13 LEVEL COLLEGE TOUR
Answer:
Initially 
of nitrogen dioxide were in the container .
Explanation:
Volume of the container at low pressure and at room temperature =
Number of moles in the container = 
After more addition of nitrogen gas at the same pressure and temperature.
Volume of the container after addition = 
Number of moles in the container after addition=
Applying Avogadro's law:
(at constant pressure and temperature)
Initially of nitrogen dioxide were in the container .
Answer:
For the determination of a structure through its NMR it is necessary to know its molecular formula as well as the delta values, its coupling and the shift of each signal.
The separation produced is called coupling constant J and is measured in Hz. If the split is produced by two equal protons (equal J) a triple signal known as triplet is produced and if produced by three equal protons, the signal is quadruple and is known as quadruplet. The magnitude of the coupling is varied, depending on the relative disposition of the coupled protons (elevations that separate them, arrangement, spatial arrangement)
OH CH2 CH2 CH2 CH2 OH
(A) (B) (C)
1,4-butanediol
In the case of the molecule to study the signal at 1.36 shows a doublet, which corresponds to the hydrogen (C), is split in two for each different proton on the same carbon or on neighboring carbons.
At 3.32 ocurrs a singlet, wich belong to hidrogen (B). The last signal is a quintet, at 4.63 belonging to the hydrogen (C)
Explanation
Nuclear magnetic resonance NMR is a physical phenomenon based on the mechanical-quantum properties of atomic nuclei. NMR also refers to the family of scientific methods that explore this phenomenon to study molecules, macromolecules, as well as tissues and whole organisms.
NMR takes advantage of the fact that atomic nuclei resonate at a frequency directly proportional to the force of a magnetic field exerted, in accordance with the Larmor precession frequency equation, to subsequently disturb this alignment with the use of an alternating magnetic field, of orthogonal orientation.
The behavior of the nuclei in the magnetic field can be influenced in multiple ways, to give different types of information, but the basic information obtained is:
- Frequency at which each particular nuclei comes out, displacement.
- Number of nucleis of each type, integral.
- Number and arrangement of nearby nuclei, multiplicity.
