Results:

The massic percentage is found using the formula:

Concentration (mol/l)± 1.9x10-4 | Initial mass ± 0.05 | Final mass± 0.05 | Massic % | Error (%) |

0.1 | 2.30 | 3.02 | 23.84 | 1.307722964 |

0.2 | 4.37 | 5.30 | 17.55 | 0.531847209 |

0.3 | 3.51 | 3.94 | 10.91 | 0.432463495 |

0.4 | 1.93 | 2.13 | 9.39 | 0.684085376 |

0.5 | 2.52 | 2.46 | -2.44 | 0.147540674 |

0.6 | 3.25 | 3.06 | -6.21 | 0.298438799 |

0.7 | 3.05 | 2.53 | -20.55 | 1.149326081 |

0.8 | 3.5 | 2.73 | -28.21 | 1.436085282 |

0.9 | 3.2 | 2.4 | -33.33 | 1.909722222 |

1.0 | 2.95 | 2.33 | -26.61 | 1.593043632 |

Evaluation:

As we can see above, there are two charts: Massic percentages and concentration of the solutions; Molar concentrations and % increase in length. The second chart shows the results of another group, who used the same method but recorded change in length rather than change in mass.

Using the equation y=-66.631x+31.081 we can find the solute concentration of the potato: as it is the x value for when y=0, we solve the equation:

0=-66.631x+31.081

We find x=0.47 so according to our experimental data the solute concentration of the potato was 0.47 mol/l.

The correlation coefficient is R2=0.95 which is very good, whereas for