THE MEANING OF WATER

The emergence of water

• WATER appeared on the surface of the Earth when the Earth was a heated sphere.
• As the temperature of the planet cooled, the water vapor condensed.
• Seas and oceans formed.
• About 200 million years ago.

Water cycle

Water in living organisms

• In the human body, about 75%
• Cucumbers 65%
• In milk 87%
• Jellyfish 97%
• In potatoes 76%

THE MEANING OF WATER

• Participates in photosynthesis.
• Transport of substances.
• Living environment.
• Participation in the fertilization process and development.
• Cycle of substances.
• Metabolism.
• Heat regulation.
• Cell composition.

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Determination of the mass fraction of water in the sample (orange)

• 10 grams of fruit samples are weighed on an electronic scale.
• Grind in a porcelain bowl.
• Holding the porcelain bowl in the crucible tongs, carefully heat it on the flame of an alcohol lamp.
• The dry residue obtained after heating is cooled.
• Weigh the dry residue.
• Calculate the percentage of water in the sample.

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W_%(for water) =m_water/m_common*100%

m_water=m_common-m_{dry residue}

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