To calculate the percentage change in mass during osmosis, you use the following formula: *((Final Mass - Initial Mass) / Initial Mass) 100%**. This tells you the relative change in mass as a percentage of the original mass.
Here's a breakdown of the process:
- Determine the Initial Mass: This is the mass of the object (e.g., potato slice, cell) before osmosis occurs.
- Determine the Final Mass: This is the mass of the object after osmosis has taken place for a specific period.
- Calculate the Difference: Subtract the initial mass from the final mass (Final Mass - Initial Mass). This gives you the absolute change in mass.
- Divide by the Initial Mass: Divide the result from step 3 by the initial mass. This gives you the change in mass relative to the original mass.
- Multiply by 100%: Multiply the result from step 4 by 100 to express the change as a percentage.
Formula:
Percentage Change in Mass = ((Final Mass - Initial Mass) / Initial Mass) * 100%
Example:
Let's say you put a potato slice in a sugar solution to observe osmosis.
- Initial Mass: 5.6 g
- Final Mass: 4.7 g
Using the formula:
Percentage Change in Mass = ((4.7 g - 5.6 g) / 5.6 g) 100%
Percentage Change in Mass = (-0.9 g / 5.6 g) 100%
Percentage Change in Mass = -0.1607 * 100%
Percentage Change in Mass = -16.07% (approximately -16%)
In this case, the negative sign indicates that the potato slice lost mass due to water moving out of the potato and into the sugar solution (a hypertonic environment). A positive percentage change would indicate a gain in mass (water moving into the object).
Importance of Percentage Change:
Calculating the percentage change is more useful than just the absolute change in mass because it allows you to compare results across different experiments or conditions, even if the initial masses of the samples were different.
