Answer: the line Spectra of hydrogen lies between the ultra-violet, visible light and infra-red of the electro magnetic spectrum
Explanation:
Electromagnetic radiation spans an wide range of wavelengths and frequencies. This range is called the electromagnetic spectrum. The electromagnetic spectrum is generally divided into seven regions, in order of decreasing wavelength and increasing energy and frequency. The 7 regions includes; radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma rays.
lower-energy radiation, such as radio waves, is expressed as frequency while microwaves, infrared, visible and UV light are usually expressed as wavelength and finally, higher-energy radiation such as X-rays and gamma rays, is expressed in terms of energy per photon.
Therefore, hydrogen lies between the ultra-violet, visible light and infra-red region of the electro magnetic spectrum.
Answer : The 
must be administered.
Solution :
As we are given that a vial containing radioactive selenium-75 has an activity of 
.
As, 3.0 mCi radioactive selenium-75 present in 1 ml
So, 2.6 mCi radioactive selenium-75 present in 
Conversion :
Therefore, the must be administered.
Answer:
magnesium metal melts = physical change
magnesium metal ignites = chemical change
Explanation:
<em>Physical changes</em> are those in which the identity of the subtance <u>remains unaltered</u>. No new compounds are formed. They involve generally changes in <u>agreggation states of matter</u>: solid, liquid or gas. The first experiment, in which magnesium metal melts is a physical change because it only changes the state of matter, from solid to liquid, but it is still magnesium metal.
Conversely, <em>chemical changes</em> involve atoms combinations to form new compounds. The second experiment, in which magnesium metal ignites, is a chemical change. After the change, magnesium metal is no longer the metal but a metal oxide.
Amphiprotic compounds are able to both donate and accept a proton.
Amphiprotic compounds contain a hydrogen atom and lone pair of valence electron.
For example, HSO₃⁻ (hydrogen sulfate ion) is an amphiprotic compound.
Balanced chemical equation for reaction when HSO₃⁻ donate protons to water:
HSO₃⁻(aq) + H₂O(l) ⇄ SO₄²⁻(aq) + H₃O⁺(aq).
Ka = [SO₄²⁻] · [H₃O⁺] / [HSO₃⁻]
Balanced chemical equation for reaction when HSO₃⁻ accepts protons from water:
HSO₃⁻(aq) + H₂O(l) ⇄ H₂SO₄(aq) + OH⁻(aq).
Kb = [H₂SO₄] · [OH⁻] / [HSO₃⁻]
Water (H₂O), amino acids, hydrogen carbonate ions (HCO₃⁻) are examples of amphiprotic species.
Another example, water is an amphiprotic substance:
H₂O + HCl → H₃O⁺ + Cl⁻
H₂O + NH₃ → NH₄⁺ + OH⁻
More about amphiprotic compounds: brainly.com/question/3421406
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