Water Hardness

OBJECTIVE:

The objective of this lab is to perform a titration using an EDTA solution to examine the hardness of a variation of different water samples and to observe temporary hardness.

DATA:

After following through the procedures of the Water Hardness lab, these are the results I obtained:

TITRATION OF CALCIUM CARBONATE SOLUTION |

INITIAL | .21 mL |

FINAL | 2.19 mL |

MOLES OF EDTA | 1.98x10^-5 |

MASS OF CACO3 | |

WEIGHT(PPM) OF CACO3 | |

HANDBOOK VALUE [CACO3]CONVERTED TO (PPM) | |

% ERROR OF MY PPM VS. HANDBOOK PPM | |

TITRATION OF A TAP WATER SAMPLE |

INITIAL | 2.19 mL |

FINAL | 8.34 mL |

MOLES OF EDTA | 6.15x10^-5 |

MASS OF CACO3 | |

WEIGHT (PPM) CACO3 | |

TITRATION OF A BOILED TAP WATER SAMPLE |

INITIAL | 8.34 mL |

FINAL | 15.61 mL |

MOLES OF EDTA | 7.27x10-5 |

MASS OF CACO3 | |

WEIGHT (PPM) CACO3 | |

TEMPORARY HARDNESS | |

TITRATION OF A SOFT WATER SAMPLE |

INITIAL | 15.61 mL |

FINAL | 16.78 mL |

MOLES OF EDTA | 1.17x10^-5 |

MASS OF CACO3 | |

WEIGHT (PPM) CACO3 | |

TITRATION OF A HARD WATER SAMPLE |

INITIAL | 16.78 mL |

FINAL | 34.81 mL |

MOLES OF EDTA | 1.80x10^-4 |

MASS OF CACO3 | |

WEIGHT (PPM) CACO3 | |

CALCULATIONS:

In the Water Hardness lab I used 5 different calculations. I used a different calculation each time to calculate the moles of EDTA, the mass of calcium carbonate, the weight (ppm) of calcium carbonate, the conversion of the handbook value for the calcium carbonate to ppm and the percent error for my ppm vs. the handbook ppm. Examples of how I used these different calculations are below:

1. How to calculate the moles of EDTA:

M · L = 0.01 M/L · .00198L = 1.98x10^-5

2. How to calculate the mass of calcium carbonate:

Moles CaCO3 (which can be found by multiplying L by M)· (molar mass/ 1 mol CaCO3) = (0.05 · · (100.09g/l / 1 mol CaCO3) =

3. How to determine the weight in...