Polar Bonds and Molecules

Which statement explains why water molecules stick together?

• both sides are negative

• one side has a positive charge and the other side has a negative charge

• one side has a negative charge adn the other side has a neutral charge

• both sides are positive

Which end of the water molecule has a slightly negative charge?

• the oxygen end

• the hydrogen end

• both ends are slightly negative

• neither end is negative

True or false water is a polar molecule? 

• True 

• False 

Which end of the water molecule has a slightly positive charge?

• the oxygen end

• the hydrogen end

• both ends are slightly positive

• neither end is positive

Which term refers to water having a slightly positive and a slighty negative charge on its ends?

• cohesion

• surface tension

• polar

• adhesion

Why does water moderate temperature so well?

• It does not allow heat in between the hydrogen bonds.

• More energy is needed to break all the hydrogen bonds, or rebuild them, between water molecules.

• Water has high energy all the time, so it can't heat up any more.

• The polarity of the water molecule resists the added energy, causing water to stay the same temperature.

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NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Why is water so good at dissolving so many substances?

• it is polar

• it is less dense as a solid

• cohesion

• adhesion

Why can water striders walk across the surface of water without falling through?

• They are light enough so they don't break the hydrogen bonds holding the water molecules together

• The insects actually use their wings to hover slightly above the water’s surface

• The insect’s feet are non-polar, so they are repelled by the polar water molecules and are pushed away from the water’s surface.

• The insects are small enough to see the individual water molecules, so they are able to step carefully from one molecule to the next

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Which of the following molecules is most likely to have polar bonds but be nonpolar overall?

• Carbon dioxide (CO2)

• Water (H2O)

• Ammonia (NH3)

• Methane (CH4)

What causes a molecule to be polar?

• Equal sharing of electrons between atoms

• Unequal sharing of electrons between atoms

• Presence of ionic bonds

• Symmetrical shape of the molecule