rock candy is formed when excess sugar is dissolved in hot water followed by crystallization. a student wants to make two batches of rock candy. he finds an unopened box of \cane sugar\ in the pantry. he starts preparing batch a by dissolving sugar in 500 ml of hot water (70°c). he keeps adding sugar until no more sugar dissolves in the hot water. he cools the solution to room temperature. he prepares batch b by dissolving sugar in 500 ml of water at room temperature until no more sugar is dissolved. he lets the solution sit at room temperature.

a pair of 100 ml samples of water are taken from a well bored into a large underground salt (nacl) deposit. sample #1 is from the top of the well, and is initially at 32°c. sample #2 is from a depth of 50. m, and is initially at 42°c. both samples are allowed to come to room temperature (20.°c) and 1 atm pressure. an nacl precipitate is seen to form in sample #1.

Question

rock candy is formed when excess sugar is dissolved in hot water followed by crystallization. a student wants to make two batches of rock candy. he finds an unopened box of \cane sugar\ in the pantry. he starts preparing batch a by dissolving sugar in 500 ml of hot water (70°c). he keeps adding sugar until no more sugar dissolves in the hot water. he cools the solution to room temperature. he prepares batch b by dissolving sugar in 500 ml of water at room temperature until no more sugar is dissolved. he lets the solution sit at room temperature.

a pair of 100 ml samples of water are taken from a well bored into a large underground salt (nacl) deposit. sample #1 is from the top of the well, and is initially at 32°c. sample #2 is from a depth of 50. m, and is initially at 42°c. both samples are allowed to come to room temperature (20.°c) and 1 atm pressure. an nacl precipitate is seen to form in sample #1.

Accepted Answer

# Explanation:
## Step1: Solubility and temperature relationship
The solubility of sugar (and $NaCl$) generally increases with temperature. For the rock - candy problem, in batch A, sugar is dissolved in hot water ($70^{\circ}C$). Since solubility is higher at higher temperatures, more sugar is dissolved in batch A compared to batch B (where sugar is dissolved at room temperature). When the solution in batch A is cooled, the solubility of sugar decreases, and more sugar will crystallize (form rock - candy) because the amount of sugar dissolved initially (at high temperature) is much larger than the solubility at room temperature.

For the $NaCl$ problem, sample #2 is initially at a higher temperature ($42^{\circ}C$) than sample #1 (initially at $32^{\circ}C$). Since the solubility of $NaCl$ increases with temperature, sample #2 can dissolve more $NaCl$ initially. When both samples are cooled to room temperature ($20^{\circ}C$), the decrease in solubility for sample #2 is larger (because it was dissolved at a higher initial temperature). So, a bigger mass of $NaCl$ precipitate will form in sample #2.

# Answer:
For the rock - candy question: It is likely that more rock candy will be formed in batch A.
For the $NaCl$ question: A bigger mass of $NaCl$ precipitate will form in Sample #2.

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Question

Explanation:

Step1: Solubility and temperature relationship

Answer: