The best and most correct answer among the choices provided by your question is the fourth choice or letter D. Natural run-off from mountain ranges <span>is thought to be most responsible for the salinity of the oceans.
</span>After years and years of river inflow and evaporation, the salt<span> content of the lake water built up to the present levels. The same process made the seas </span>salty<span>. Rivers carry dissolved salts to the </span>ocean<span>. Water evaporates from the </span>oceans<span> to fall again as rain and to feed the rivers, but the salts remain in the </span>ocean<span>.</span>
The most common method astronomers use to determine the composition of stars, planets, and other objects is spectroscopy. This process utilizes instruments with a grating that spreads out the light from an object by wavelength. This spread-out light is called a spectrum. Every element has a unique fingerprint that allows researchers to determine what it is made of.
The fingerprint often appears as the absorption of light. Every atom has electrons, and these electrons like to stay in their lowest-energy levels. But when photons carrying energy hit an electron, they can push it to higher energy levels. This is absorption, and each element’s electrons absorb light at specific wavelengths related to the difference between energy levels in that atom. But the electrons want to return to their original levels, so they don’t hold onto the energy for long. When they emit the energy, they release photons with exactly the same wavelengths of light that were absorbed in the first place. An electron can release this light in any direction, so most of the light is emitted in directions away from our line of sight. Therefore, a dark line appears in the spectrum at that particular wavelength.
Because the wavelengths at which absorption lines occur are unique for each element, astronomers can measure the position of the lines to determine which elements are present in a target. The amount of light that is absorbed can also provide information about how much of each element is present.
The oxidation half-reaction occurs at one electrode (the anode), and the reduction half-reaction occurs at the other (the cathode). When the circuit is closed, electrons flow from the anodeto the cathode.
moles Cu produced : 0.002
<h3>Further explanation</h3>
Concentration of copper sulfate (CuSO₄) : 0.319 g/dm³
MW CuSO₄ :
mol CuSO₄ /dm³ :
CuSO₄⇒Cu²⁺ + SO₄²⁻
mol Cu : mol CuSO₄ = 1 : 1 , so mol Cu²⁺=0.002
