30 POINTS FOR THIS! Copper (Cu) reacts with sulfur (S) to form copper sulfide. A scientist adds 12.7 grams of Cu to 3.2 grams of S to start the reaction. At the end of the experiment, there are 15.9 grams of copper sulfide. In this reaction, all of the copper and all of the sulfur react. The scientist then tries to add 13.7 grams of Cu to 3.2 grams of S. There are still 15.9 grams of copper sulfide at the end, but some copper is also left over. In 1-2 sentences, explain how to calculate the amount of remaining copper. Use the law of conservation of mass in the explanation.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally