Answer: Option (D) is the correct answer.
Explanation:
Need means necessity without which a person might not be able to survive for long.
For example, food is a need for every living being as without it any individual cannot survive for a long period of time.
Similraly, shelter is also a need and insurance is also necessary as it protects an individuals life or his savings so that after his death the future of his family remains protected.
Whereas cable TV is not a need as an individual can survive without it. Therefore, a cable TV is a want.
Whenever new evidence is discovered we must make changes in order to adapt theories to the current base of knowledge. If we were to simply never change any scientific theory, then they would likely no longer stand as factual credible pieces of information in the future.
<span>When two metals touch in the mouth, a small shock is created. this is known as a </span>galvanic action
<u>Given:</u>
Mass of Ag = 1.67 g
Mass of Cl = 2.21 g
Heat evolved = 1.96 kJ
<u>To determine:</u>
The enthalpy of formation of AgCl(s)
<u>Explanation:</u>
The reaction is:
2Ag(s) + Cl2(g) → 2AgCl(s)
Calculate the moles of Ag and Cl from the given masses
Atomic mass of Ag = 108 g/mol
# moles of Ag = 1.67/108 = 0.0155 moles
Atomic mass of Cl = 35 g/mol
# moles of Cl = 2.21/35 = 0.0631 moles
Since moles of Ag << moles of Cl, silver is the limiting reagent.
Based on reaction stoichiometry: # moles of AgCl formed = 0.0155 moles
Enthalpy of formation of AgCl = 1.96 kJ/0.0155 moles = 126.5 kJ/mol
Ans: Formation enthalpy = 126.5 kJ/mol
Avogadro's number tells you that in one mol of element (sulfur) there are 6.022x10^23 atoms...
So,
1 mol : 6.022x10^23 = x mol : 1.2x10^2
x = 1.99 x 10^-22 mol
*Although this should be correct, you might want to check your question again. You probably misinterpret the question... you want 1.2x10^23 !! :) check it.
