Aminaali

Determining the Water Gain/Loss of a Potato

Amina Ali

SCH3U

Mrs. Fife

03/01/16

Purpose: This lab was conducted to determine the solute concentration of a potato.

Materials: Refer to Investigation 1, section 3.2, “A study of Osmosis: Determining the Solute Concentration of Potatoes” on page 80-81 of Addison-Wesley Biology 11.

Please note that a stirring rod, duck tape & 6 test tube corks, one 250mL & one 100ml beaker was used instead of two 100mL, and only one pipette were added to the experiment.

Procedure: Refer to Investigation 1, section 3.2, “A study of Osmosis: Determining the Solute Concentration of Potatoes” on page 80-81 of Addison-Wesley Biology 11.

Observations:

The Potatoes Change in Mass

Test Tube | Solute Concentration (mol-L-1) | Initial Mass I(g) | Final Mass F(g) | Change in Mass(F-I)(g) | Percent Change in Mass (F-I/1) x 100 |

1 | 0 | 5.6 | 6.4 | 0.8 | 14.28% |

2 | 0.2 | 5.3 | 5.6 | 0.3 | 5.66% |

3 | 0.4 | 5.4 | 5.4 | 0 | 0% |

4 | 0.6 | 5.4 | 4.6 | -0.8 | -14.81% |

5 | 0.8 | 5.5 | 4.7 | -0.8 | -14.54% |

6 | 1.0 | 5.4 | 4.3 | -1.1 | -20.37% |

Graph:

Analysis:

Q1. The solute concentration of the potatoes by interpolation is 0.4 because that is when there is no change in mass.

Q2. Refer to the graph, “Solute Concentration of Potatoes”

Q3. The reason why some potato sections gained mass and others lost mass is because the potatoes weren’t put into the same solute concentration. The potatoes that were put into solutions that had more to all salt, diffused into the solution attempting to dilute it, which resulted the potato piece to weigh less (Hypertonic). The potatoes that were put into solutions that had more to all distilled water gained mass because the distilled water tried to lower the concentration within the potato (Hypotonic).

Q4. I think my experimental results are accurate because of the lack of errors in the experiment. When there was more distilled water the mass of...