Answer:
The hydrogen spectrum is an important piece of evidence to show the quantized electronic structure of an atom. ... It results in the emission of electromagnetic radiation initiated by the energetically excited hydrogen atoms. The hydrogen emission spectrum comprises radiation of discrete frequencies.
The spectrum starts with red light, with a wavelength of 700 nanometers (7,000 angstroms), at the top. ... It spans the range of visible light colours, including orange and yellow and green, and ends at the bottom with blue and violet colours with a wavelength of 400 nm (4,000 angstroms).
Explanation:
Hydrogen molecules are first broken up into hydrogen atoms (hence the atomic hydrogen emission spectrum) and electrons are then promoted into higher energy levels. Suppose a particular electron is excited into the third energy level. It would tend to lose energy again by falling back down to a lower level.
The spectrum of the Sun appears as a continuous spectrum and is frequently represented as shown below. This type of spectrum is called an emission spectrum because what you are seeing is the direct radiation emitted by the source.
Answer: B. Metal
Explanation: The catalyst used in the converter is mostly a precious metal such as platinum, palladium and rhodium Hope This Helped (=^･-･^=)
Answer:
<em>249 kJ</em>
Explanation:
To obtain the energy change of the reaction:
H₂O → H₂ + ¹/₂ O₂
It is necessary to obtain the difference between bond energy of the products and bond energy of the reactant, thus:
Energy of products:
1 mol of H-H bond × 436 kJ/mol = 436 kJ
¹/₂ mol of O=O bond × 498 kJ/mol = 249 kJ
Energy of reactant:
2 mol of H-O bond × 467 kJ/mol = 934 kJ
Energy change of the reaction is:
934 kJ - (436 kJ + 249 kJ) = <em>249 kJ</em>
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I hope it helps!
