Moles Review Quiz

A water molecule has the chemical formula H₂O. This means that the water molecule is made up of

• Two hydrogen atoms and one oxygen atom

• Two oxygen atoms and one hydrogen atom

• Two hydrogen atoms and two oxygen atoms

• Two molecules of water

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The atoms in a water molecule are held together by covalent bonds. This means that the bonded atoms

• Lose protons

• Lose electrons

• Share electrons

• Switch neutrons

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The water molecule is a polar molecule. A water molecule is polar because

• The electrons are shared equally

• Oxygen has a stronger attraction for electrons than hydrogen

• It is very cold

• Hydrogen atoms have a stronger attraction for electrons than oxygen

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The water molecule is

• Slightly negative near the hydrogen atoms and slightly positive near the oxygen atom

• Slightly positive in all areas of the molecule

• Slightly negative near the oxygen atom and slightly positive near the hydrogen atoms

• The same charge in all areas of the molecule

Water molecules are attracted to each other because

• They are all positively charged

• Each water molecule has the same number of protons as electrons

• The positive area of one water molecule is attracted to the negative area of another

• All water molecules are neutral

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A paper clip can stay on the surface of water because of water's strong surface tension. Water's surface tension is mostly a result of

• Water's temperature

• The motion of water molecules

• The attraction of water molecules

• The impurities in the water

Water cannot dissolve all substances that are made from ionic bonds. This is probably because

• Some water molecules are not as strong as others

• Water needs to be stirred to dissolve all ionic substances

• Some ionic bonds are too strong for the attractions of water molecules to pull them apart

• Water needs to be heated to dissolve all ionic substances

Water beads up on the surface of a penny because of this property.

• Adhesion
• High Surface Tension
• Universal Solvent
• Changes in Density

What type of intermolecular force does water experience?

• dispersion

• dipole

• covalent

• hydrogen "bond"

Why does oil and water not mix together?

• because both compounds are polar

• because both compounds are nonpolar

• because water is polar and oil in nonpolar

• because water is nonpolar and oil in polar

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