Question

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 NaC1 precipitate is seen to form in Sample #1.

a. A trigger mass of NaCT precipitate will farm in Sangle #2
b. A smaller mass of NaCl precipitate will formin Sample #
c. The same mass of NaCl precipitate will form in Sample #
d. No precipitate will form in Sample

Answer 1

The formation of NaCl precipitate is temperature and pressure dependent. A larger mass of NaCl precipitate forms in Sample #1 due to the decrease in temperature compared to Sample #2. A smaller mass of NaCl precipitate forms in Sample #3 due to the higher pressure at a depth of 50m.

Step-by-step explanation:

When water is saturated with a salt like NaCl, the solubility of the salt is temperature dependent. As the temperature decreases, the solubility of NaCl decreases, causing the salt to precipitate out of solution.

In Sample #1, which is initially at 32°C and is allowed to come to room temperature (20°C), the decrease in temperature causes the NaCl to precipitate, forming a larger mass of NaCl precipitate compared to Sample #2, which is initially at 42°C and also allowed to come to room temperature. In Sample #3, which is initially at a depth of 50m, the higher pressure at that depth increases the solubility of NaCl, resulting in a smaller mass of NaCl precipitate compared to Sample #1. Finally, since the concentration of NaCl in both Sample #1 and Sample #2 is the same at room temperature, the same mass of NaCl precipitate would form in both samples.