Water, pH and Macromolecules
Polyprotic acids such as H3PO4, can act as acid-base buffers

at pH values around neutrality
at pH values around any of their pKa's
if their concentration is kept low
only in combination with polyprotic bases

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Water, pH and Macromolecules
Which of the following statements about covalently bonded molecules is false?

The chemical bonds that hold the molecule together are relatively strong
Noncovalent bonds may also be present, especially if the molecule is large
Electrons are shared between the atoms that make up the molecule
Such molecules often result from the interaction of ionized atoms

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Water, pH and Macromolecules
Which of the following statements about water is correct?

All of these
Polar substances that can form hydrogen bonds will dissolve in it
Nonpolar substances like oils are not soluble in it
It is critical for many of the chemical processes found in living systems

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