Three gas phase systems are studied. The first consists of Ca 2+ and S 2- at 300
ID: 889729 • Letter: T
Question
Three gas phase systems are studied. The first consists of Ca2+ and S2- at 300 nm; the second is two uranium nuclei separated by 154 pm and the third is a chloride ion and iodide ion positioned 45 apart. Answer the following questions without using a calculator.
Which of these systems will give a negative E when separated to infinite distance? (Select all that apply.)
chloride and iodide
uranium nuclei
Ca2+ and S2-
Which of these three systems has the largest magnitude electrostatic potential, Eel? (Select all that apply)
uranium nuclei
Ca2+ and S2-
chloride and iodide
Explanation / Answer
1 ) answer : Ca+2 and S-2
explanation :
CaS distance = 300 nm = 300 x 10^-9 m = 3 x 10^-7 m
Uranium nuclie distance = 154pm = 154 x 10^-12 = 1.54 x 10^-10 m
ClI distance= 45Ao = 45 x 10^-8 = 4.5 x 10^-7 m
so comparing these three uranium nuclie distance is smaller than the other. so we need to give more energy to seperate them . so for greater distance between Ca+2 and S-2 large . so little amount energy needed. so large delta E
2) largest magnitude of electrostatic potential for Ca+2 and S-2
explanation : because CaS is itself ionic compound. so there are electrostatic attractions works inbetween Ca+2 and S-2
.