Question

Below, is a completed lab. After completing this lab, I was asked the following question:

What changes would you make, if any, if you did this lab again?

I'm having a hard time thinking of what I would do different. Please help!

Observations & Questions for Part 1

Record your observations and your time and temperature data in tables. Use one table for the pure water and one table for the salt solution.

Data Table 1: Pure Water and Salt Solution
Seconds	Distilled H20 Room temp	Distilled H20 Ice bath	Saltwater Room temp	Saltwater Ice bath
0	23	23	17	23
30	23	10	20	7
60	23	4	22	1
90	22.5	1	22	0
120	22.5	0	22	0
150		0	22	-1
180		-1	22	-1
210		-1	22	-2
240		-2		-2
270		-1		-2
300		-1		-2
330		-1		-2
360		-1
390		0
420		0
450		0
480		0
510		0
540
570
600
630
660

Make two graphs of your data. On one graph plot the data from the pure water. On the other graph plot the data from the salt solution. On both plot temperature on the y-axis and time on the x-axis.

A. Record the freezing point of the pure water and the freezing point of the salt solution.

Freezing point of salt Sol: -2 degree Celsius

Freezing point of pure H2O: 0 degree Celsius

B. How do these two freezing points compare?

The freezing point of salt water is lower than the freezing

point of fresh water. Salt in the water lowers the freezing point

of water.

C. What are some practical applications of freezing point depression, boiling point elevation, and vapor pressure lowering?

Some practical applications of freezing point depression

are antifreeze in a radiator and salt on the road used to melt

ice in the winter. Some practical applications of boiling point

elevation are a sealed container and possibly a pressure cooker.

Some practical applications of vapor pressure lowering are freeze

drying and steam engines.

Questions - Part 2

To what biological structure is the dialysis bag comparable? How is it similar? How is it different?

The plasma membrane is comparable to the dialysis bag.

The similarity between them is that they are both semipermeable.

The difference is the dialysis bag acts as a permeable membrane,

however, purely based on its pore size, the small molecules are

able to get through but the bigger molecules are unable to. The

plasma membrane is a more complex system that uses both active

and passive transport to allow the molecule to move through.

In biological systems if a cell is placed into a salt solution in which the salt concentration in the solution is lower than in the cell, the solution is said to be hypotonic. Water will move from the solution into the cell, causing lysis of the cell. In other words, the cell will expand to the point where it bursts. On the other hand, if a cell is placed into a salt solution in which the salt concentration in the solution is higher than in the cell, the solution is said to be hypertonic. In this case, water will move from the cell into the solution, causing cellular death through crenation or cellular shrinkage. In your experiment is the Karo