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Explain why ionic substances dissolve in water.Like an explanation why they dissolve in...

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publicspeaker | Student, Grade 11 | (Level 1) Honors

Posted October 31, 2010 at 3:05 AM via web

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Explain why ionic substances dissolve in water.Like an explanation why they dissolve in water and what causes it to dissolve in water like the chemical reactions involved.

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ndnordic | High School Teacher | (Level 2) Associate Educator

Posted October 31, 2010 at 6:29 AM (Answer #1)

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Because of the structure of water, it is a polar molecule. That means that the hydrogen atoms have a slightly positive charge, and the oxygen atom has a slightly negative charge.

Ionic compounds are crystals with equal numbers of positive and negative ions. When these ionic compounds are put in water the water molecules start to attract the ions, separating them from each other. The hydrogen atoms of the water molecules are closest to the negative ions of the compound, and the oxygen atoms of the water are closest to the positive ions of the ionic compound.

Picture each of the ions of the ionic compound being surrounded by water molecules and that will give you an idea of what is happening, but at a very fast rate once the compound is added to water.

This is just a physical change since if the water is removed the ionic compound is recovered unchanged.

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suzy555 | Student, Grade 10 | (Level 1) Salutatorian

Posted November 6, 2010 at 12:31 AM (Answer #2)

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ionic substances dissolve in water since their molecules can be separeted in water and then form another bonds with water's molecules.

the water consists of 2 hydrogen atoms and one oxygen atom and for example the sodium chloride dissole in water how?

Oxygen has a higher electronegativity than Hydrogen so scientists say that (in water molecule) Oxygen is negatively charged while Hydrogen is positively charged and therefore positively charged sodium molecule(s)  bec. sodium is a metal make a bond with oxygen {positive+negative}

While negatively charged chlorine molecule(s) as chlorine is non-metal make a bond with positively charged Hydrogen.

Never forget that water is a good polar solvent which means that many elements can dissolve in water easily. 

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