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Grade 10 Science · Problem type
Why ice floats
Use this for “Why does ice float on liquid water?”, “How many hydrogen bonds can one water molecule make?” or “Why does water dissolve salt?”
Explore
The oxygen pulls the shared electrons harder than the hydrogens do.
The two lone pairs bend the molecule, so its charges don’t cancel.
Its 2 H atoms and 2 lone pairs are 4 places for hydrogen bonds, so it holds at most 4 neighbors.
Assumptions
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Water is bent and polar: its O is partly negative and its H atoms partly positive.
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A hydrogen bond pulls an H of one molecule to a lone pair on another; it is much weaker than a covalent bond.
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Chemical equations: balancing, types of reactions and predicting products
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