• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9

Osmosis in Potatoes Lab. At which concentration of sucrose in water (% mass by sucrose) will the potato core be isotonic, meaning that there is no movement of water in or out of the potato core?

Extracts from this document...

Introduction

Osmosis in Potatoes Date of Experiment: Feb. 4, 2009- Feb. 6, 2009 Research Question: At which concentration of sucrose in water (% mass by sucrose) will the potato core be isotonic, meaning that there is no movement of water in or out of the potato core? Hypothesis: If the percent mass by sucrose of the solution is in between 10 and 30 percent, then the solution would be isotonic, meaning that no osmosis occurs between the potato and the solution. I assume this because the percent change before and during 10 percent indicates water moving into the potato (hypotonic), and the percent change during and after 30 percent mass by sucrose indicates that water is moving out of the potato (hypertonic). Variables: > Independent: o Percent of mass by Sucrose in each solution > Dependent: o Percent change in mass of potato cores > Control: o Length of time each core stayed in solution o Size of each potato core o Amount of solution in each test tube o Temperature of solution and surrounding area o Potato from which the cores come from Materials: o Potato Electronic Scale o Cork Borer 6 Test Tubes o Tweezers Beaker o Water with different amounts of Sucrose (0%-50% by mass) ...read more.

Middle

o (7.5%+ 1.79+ -3.12)/ 3= 2.06% 10% Mass by Sucrose in Solution o (1.82%+ 6.89+ 4.16)/ 3= 4.29% 20% Mass by Sucrose in Solution o (1.89%+ 8.38+ 4.16)/ 3= 4.81% 30% Mass by Sucrose in Solution o (-8.81%+ -36.69+ -9.19)/ 3= 18.23% 40% Mass by Sucrose in Solution o (-13.72%+ -48+ -19.2)/ 3= -26.97% 50% Mass by Sucrose in Solution o (-17.08%+ -51.79+ -33.04)/ 3= -33.97% > Step 4: Put the average changes in mass into a graph, find the line of best fit, and using the equation of the line of best fit, find the point when the solution is isotonic. Then, find the moles of sucrose in the isotonic solution, and find the ratio of moles between the sucrose and water. Graph 1: Average Change in Mass of Potato Cores At what percent mass by sucrose is the solution isotonic? o y= -0.8485x+9.8771 o Plug "0" in for "y": 0= -0.8485x+9.8771 o Work out the equation, and find the value for "x": 0= -0.8485x+9.8771 -9.8771= -0.8485x x= 11.64 When the solution has a 11.64 percent mass by sucrose, then it will be isotonic because then the average percent change would be 0%, meaning that no water is moving in or out of the potato. Finding the number of moles: In order to find the number of moles of sucrose in the isotonic solution, we have to find the molar mass, and mass of the solution. ...read more.

Conclusion

Once again, we head back to the possibility of imperfections in things such as measurements, and how there is a very slim chance that each test tube contained an EXACT amount of sucrose by mass, meaning that it is highly unlikely that the test tube labeled with 10% concentration of sucrose had exactly 10% sucrose by mass. These inaccurate measurements could have affected what the equation for our line of best fit was, and thus, again, affecting the outcome of our final answer. Another problem encountered was how the potato cores in solutions with less concentrations of sucrose would float to the top, sometimes with parts of the core above the surface of the water. This could affect our recordings of mass because some of the water that was stored in the top of our potato never moved out because it was never completely submerged, or vice versa. One last thing I noticed is that when we took the potato cores out to measure the masses, we drained out some of the water, and didn't place it back into the test tube. This could maybe affect the amount of water that is left to move into the potato, or maybe even effect the final measuring of mass. The point is that there are many little factors, events, and disturbances that may not seem like much, but when they are all added up, they can change, sometimes drastically, your final answer. ?? ?? ?? ?? 1 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

5 star(s)

*****
A detailed account of an investigation with a very specific aim. Good data processing and graph.

Marked by teacher Adam Roberts 20/05/2013

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Life Processes & Cells essays

  1. Marked by a teacher

    Isotonic Point of Potatoes

    5 star(s)

    * After a period of time, the change in mass of the potato slices will be obtained. A graph would be plotted of concentration against percentage change in mass. * From the graph the concentration where there is no change in mass can be obtained, hence the isotonic point of the potato can be determined.

  2. Investigating the effect of changing the concentration of an acid on the rate of ...

    This made my average accurate, so my best fit line would be more accurate. For several reasons I did obtain some blatant anomalies- and they are all highlighted in red on the results table (page 6). Using these to calculate the average time for each data point would have been

  1. The effect of acid on the cell membrane

    However, if I take the maximum and minimum values, the same trend can be seen in these results, which can therefore support my hypothesis. Another way to minimise these error bars would be to take more readings to make my results more accurate and reliable.

  2. Aim To determine the water potential of a potato tuber cell

    This is because the concentration of water was higher in the potato cylinders and lower in the solution. The mass of each potato cylinder put in a low concentration of water, decreased because more water molecules were getting out of the potato cylinders, into the solution.

  1. Agard Block: To investigate the effect of a differing Surface Area: Volume ratio on ...

    ==> While testing for the Surface area, the Volume was kept constant at 1cm3. ==> While testing for the Volume, the Surface area was kept constant at 20cm2. ==> Atmospheric conditions were not changed and were kept constant throughout the experiment.

  2. An introduction to osmosis.

    If the amount of sugar outside the cell is less than that inside the cell, this means that the solution is hypotonic to the cells of the potato chip. In the first beaker, the water is more sugary than the inside, so the water will come out of the beaker to balance the amount of sugar.

  1. The Effect of Glucose Concentration on the Rate of Osmosis

    � Scalpel to cut the potato cylinder. � Mat to cut the potatoes on it. � Stop watch to measure the 24 minutes. � Set of scales (accurate to 1/100 of a gram) to measure the potato chips mass. � Filter to dab the potato chips.

  2. An Investigation to determine the Water potential of Potato cells.

    Anybody found doing so will be permanently banned. Cylinders 8N1 from 8N1 coursewrok 8N1 work 8N1 info 8N1 3.20 Foucault refuted shayon's rationalisation . 0.00 shayon, please do not redistribute this dissertation. We work very hard to create this website, and we trust our visitors to respect it for the good of other students.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work