Question
Three lab groups carried out an experiment to identify the concentration of sucrose in six solutions. Each unknown solution (1-6) contained one of the following sucrose concentrations: 0.0 M, 0.2 M, 0.4 M, 0.6 M, 0.8 M, and -1.0 M. Cubes of sweet potato (1 cm3) were soaked for 24 hours in each solution and weighed to determine the change in mass. Each data entry represents the average of three sample replicates expressed as percent change in mass following a 24-hour soak in the unknown solutions. From the data provided, which unknown solution has a molarity that most closely reflects the molarity of sweet potato cells?
Unknown Percent Change in Mass Percent Change in Mass Percent Change in Mass
Group 1 Group 2 Group 3
1 6.6 7.8 7.5
2 3.1 3.7 2.9
3 -2.7 -3.5 -2.5
4 0.7 0.5 1.1
5 -11.6 -12.3 -12.6
6 -5.2 -6.2 -4.9
2
4
3
5
Unknown Percent Change in Mass Percent Change in Mass Percent Change in Mass
Group 1 Group 2 Group 3
1 6.6 7.8 7.5
2 3.1 3.7 2.9
3 -2.7 -3.5 -2.5
4 0.7 0.5 1.1
5 -11.6 -12.3 -12.6
6 -5.2 -6.2 -4.9
2
4
3
5
Answers
GPT-4o mini
To determine which unknown solution has a molarity that most closely reflects the molarity of sweet potato cells, we need to analyze the percent change in mass for each solution. The key concept is that the percent change in mass provides insight into the osmotic behavior of the sweet potato cells in the solution.
1. **Positive Percent Change in Mass**: This indicates that the solution has a lower sucrose concentration than the sweet potato cells, resulting in water moving into the cells (hypotonic solution).
- Unknowns 1 (6.6%), 2 (3.1%), and 4 (0.7%) show positive percent changes.
2. **Negative Percent Change in Mass**: This indicates that the solution has a higher sucrose concentration than the sweet potato cells, drawing water out of the cells (hypertonic solution).
- Unknowns 3 (-2.7%), 5 (-11.6%), and 6 (-5.2%) show negative percent changes.
3. **Percent Change Approaching Zero**: The molarity of the solution close to the molarity of the sweet potato cells would likely show a percent change in mass that approaches zero, indicating isotonic conditions where there is no net movement of water into or out of the cells.
- Unknown 4 (0.7%) has the least percent change in mass, suggesting that it is most isotonic with the sweet potato cells.
By analyzing the data:
- Unknown 1 has a significant increase (6.6%).
- Unknown 2 also has a positive change (3.1%).
- Unknown 3 shows a small loss (-2.7%).
- Unknown 4 shows a minimal change (0.7%).
- Unknown 5 has a significant loss (-11.6%).
- Unknown 6 also shows a noticeable loss (-5.2%).
The solution with the percent change in mass closest to zero is **Unknown 4 (0.7%)**. Therefore, the unknown solution that most closely reflects the molarity of sweet potato cells is **solution 4**.
1. **Positive Percent Change in Mass**: This indicates that the solution has a lower sucrose concentration than the sweet potato cells, resulting in water moving into the cells (hypotonic solution).
- Unknowns 1 (6.6%), 2 (3.1%), and 4 (0.7%) show positive percent changes.
2. **Negative Percent Change in Mass**: This indicates that the solution has a higher sucrose concentration than the sweet potato cells, drawing water out of the cells (hypertonic solution).
- Unknowns 3 (-2.7%), 5 (-11.6%), and 6 (-5.2%) show negative percent changes.
3. **Percent Change Approaching Zero**: The molarity of the solution close to the molarity of the sweet potato cells would likely show a percent change in mass that approaches zero, indicating isotonic conditions where there is no net movement of water into or out of the cells.
- Unknown 4 (0.7%) has the least percent change in mass, suggesting that it is most isotonic with the sweet potato cells.
By analyzing the data:
- Unknown 1 has a significant increase (6.6%).
- Unknown 2 also has a positive change (3.1%).
- Unknown 3 shows a small loss (-2.7%).
- Unknown 4 shows a minimal change (0.7%).
- Unknown 5 has a significant loss (-11.6%).
- Unknown 6 also shows a noticeable loss (-5.2%).
The solution with the percent change in mass closest to zero is **Unknown 4 (0.7%)**. Therefore, the unknown solution that most closely reflects the molarity of sweet potato cells is **solution 4**.