Part A In the simulation, select the Slightly Soluble Salts tab. Choose a salt f

ID: 507394 • Letter: P

Question

Part A

In the simulation, select the Slightly Soluble Salts tab. Choose a salt from the dropdown menu to the right. Mouse over the salt shaker, and move your mouse up and down while clicking the left mouse button to add salt to the container of water. You can also add and remove water from the container by moving the sliders on the faucets back and forth. Adjust the water level to a default volume of 1.0×1016 L. Select a salt from the dropdown list, and then add 6 cations to the water. You can input the number 6 in the box named "Total" in the table that describes the salt properties.

When the total number of cations is set to 6, the anions will be added to maintain charge neutrality. You can read the total number of cations and anions from the table.

Use the data displayed in the table for each given salt to arrange them in order of decreasing entropy when one formula unit of each type of salt is dissolved.

Rank from high entropy to low entropy. To rank items as equivalent, overlap them.

Salt Mercury ll) Bromide lons Mercury (I) 10 Dissolved Bound 10 D Tota Bromide 20

Explanation / Answer

Note down the formula of the compounds:

Silver bromide = AgBr

Thallium (I) sulfide = Tl2S

Strontium phosphate = Sr3(PO4)2

Silver arsenate = Ag3AsO4

Mercury (II) bromide = HgBr2

Copper (I0 iodide = CuI

Decompose one formula unit of each salt above to find the total number of ions.

Salt

Decomposition reaction for one formula unit of the salt

Total number of ions

AgBr

AgBr -----> Ag+ + Br-

Tl2S

Tl2S -----> 2 Tl+ + S2-

Sr3(PO4)2

Sr3(PO4)2 ----> 3 Sr2+ + 2 PO43-

Ag3AsO4

Ag3AsO4 -----> 3 Ag+ + AsO4-

HgBr2

HgBr2 -----> Hg2+ + 2 Br-

CuI

CuI ----> Cu+ + I-

The entropy is defined as the randomness of the system. The ions move in a solution in a completely random manner. The more the number of ions in a solution, the higher will be the random motions and hence higher will be the entropy.

The maximum number of ions derived from one formula unit of a salt is 5 and hence Sr3(PO4)2 will have the highest entropy. The lowest number of ions in the solution is 2 and hence both AgBr and CuI will have the lowest entropy.

Thus, the order of decreasing entropy (high entropy to low entropy) is given by

Sr3(PO4)2 > Ag3AsO4 > Tl2S HgBr2 > AgBr CuI (ans).