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Testing the hardness of water

Description

Soap solution is used to measure the hardness of rain water, temporarily hard water and sea-water. The effect of boiling the hard water samples is investigated.

Credits

:
This is an experiment from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry.
testing-the-hardness-of-w...



Apparatus Chemicals

Eye protection

Measuring cylinders (10 cm3), 5 (one for each of A to E below)

Each group of students will need:

Conical flask (100 cm3)

Bung, to fit the conical flask

Burette and burette stand

Small funnel

Soap solution (HIGHLY FLAMMABLE, HARMFUL), 75 cm3 per group (Note 1)

A supply of distilled or deionised water for rinsing their flask between experiments

Solutions as below, about 20 cm3 per group:

A Deionised water – labelled as Rain water

B A 50/50 mixture of temporarily and permanently hard water – labelled as Sea-water

C Temporarily hard water (Note 2) – labelled as Temporarily hard water

D Deionised water – labelled as Boiled temporarily hard water

E Permanently hard water diluted 50/50 with deionised water (Note 3) – labelled as Boiled sea-water

Refer to Health & Safety and Technical notes section below for additional information.

 






 


Soap solution is used to measure the hardness of rain water, temporarily hard water and sea-water. The effect of boiling the hard water samples is investigated.

ADDITIONAL INFORMATION

This is a resource from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry. This collection of over 200 practical activities demonstrates a wide range of chemical concepts and processes. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. Practical Chemistry activities accompany Practical Physics and Practical Biology .