LE S S ON 4
Activity (3)
Discovering the neutralization of water
Substance and tools * Basin containing pure water. * Two litmus papers (red - blue). Steps :
F ig (11)
What is the effect of putting both of litmus papers in pure water ? (Fig. 11) .................................................................................................................................................
From the previous we conclude that The pure water has a neutral effect on both of litmus papers ( red and blue).
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Its resistance to analysis At normal conditions, water isn’t analyzed into two elements or by the effect of heat, it helps to keep water solutions in the cells of living organisms generally. You can participate with your classmates to do this activity (Electrolysis of water).
Activity (4)
Investigating the process of electrolysis of water.
Substances and tools * A round piece of foam plate. * Two pencils. * Sodium carbonate spoon. * Water. * Empty plastic bottle. * Two copper wires. * Battery 4.5 v. * Wax gun. * Two test tubes.
) A ( )B(
Steps : )C( Cut the top of the plastic bottle and fill it to its middle with water and dissolve sodium carbonate in it. F ig (12) Make a hole in the foam as in f ig. (12). Remove carefully the wooden part of the two pencils until graphite appears, coil the copper wire around them as in f ig. (12 B). Cover the bared part by wax gun. Form the apparatus as in f ig. (13 C) and close the circuit for 10 minutes.
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