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


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.


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.


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. Factors Affecting Osmosis.

    This can be called incipient plasmolysis, incipient meaning about to be. OSMOSIS IN ANIMAL CELLS Osmosis in animal cells is irrelevant to my investigation but nethertheless I will explain briefly what occurs in animal cells during osmosis When an animal cell is placed in a hypertonic solution (e.g.

  2. The effect of acid on the cell membrane

    However, in Graph 2 the error bars I have drawn are relatively small, with one notable exception at 0.001 molar, and I can therefore have confidence in my results. My Graph 1 has large anomalies, indicating great variation in my results.

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

    Change in mass (g) Percentage of mass loss (%) 1st try 2nd try 0.0 1.60 1.60 2.00 2.00 2.00 +0.40 +25.00 0.2 1.70 1.70 1.90 1.90 1.90 +0.20 +11.76 0.4 1.50 1.50 1.45 1.45 1.45 -0.05 -3.33 0.6 1.60 1.60 1.20 1.40 1.30 -0.30 -18.75 0.8 1.50 1.50 1.00 1.10 1.05 -0.45 -30.00 1.0 1.50 1.50 0.85 0.81 0.83

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

    After that I will take the potato chips off the test tubes one by one and dab it using the filter, to get rid of the excess water that can provide me with inaccurate weights, before recording their new weights and lengths.

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

    I will also use the same volume of acid. This time I will use a boiling tube if that is what is available- the tube used is unimportant, and I will use a straw, to save time during the practical.

  2. How Temperature Affects the Movement of Pigment Through Cell Membranes

    whereas the fatty acid tails can not (hydrophobic). In the phospholipids bilayer, the hydrophilic heads are always on the outside of the membrane. The hydrophobic tails are always on the inside of the membrane. The purpose of a cell membrane is to control the transport of substances moving into and out of a cell.

  1. An experiment to investigate the effects of sucrose solution on Osmosis in potatoes chips.

    This analogy is as the sucrose concentration increases. The graph does not support all of my original predictions that I stated in the planning. Evaluation: In my opinion the experiment was not a total success. This is because of an error in the 0.2m solution.

  2. An introduction to osmosis.

    The equipment I will be using is: 1. Six test tubes 5. Measuring cylinder 2. Sugar 6. Filter 3. Potato 7. Scales 4. Potato corker 8. Test tube rack Stacey Owen Candidate no: 0126 Hampton Community College I will place the six test tubes in the rack. I will then label each test tube from 1-6.

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