Water and Life: Quiz - BWHS

What does "polar" mean?

• A molecule is cold

• A molecule has ionic bonds

• A molecule has covalent bonds

• A molecule has areas of positive and negative charge

Answer explanation

'Polar' refers to a molecule having areas of positive and negative charge due to uneven distribution of electrons. This characteristic distinguishes polar molecules from nonpolar ones, which have a more uniform charge distribution.

This atom in a water molecule has more of a negative charge

• Oxygen

• Hydrogen

Answer explanation

In a water molecule (H2O), the oxygen atom is more electronegative than hydrogen atoms. This causes the oxygen to attract electrons more strongly, resulting in a partial negative charge on the oxygen atom.

Refer to the picture of water sticking to a leaf; this is occurring because of:

• Adhesion

• Cohesion

Answer explanation

Water sticking to a leaf is due to adhesion, which is the attraction between different substances, in this case, water molecules and the leaf surface. Cohesion refers to the attraction between water molecules themselves.

Attractions between water molecules are called

• Covalent bonds

• Ionic bonds

• Polar bonds

• Hydrogen bonds

Answer explanation

Attractions between water molecules are primarily due to hydrogen bonds. These are weak interactions that occur between the positively charged hydrogen atoms of one water molecule and the negatively charged oxygen atoms of another.

Why do ice cubes float in a  glass of water?

• the ice cubes are more dense than the water

• the water is more dense than the ice cubes

• the water is more dense than the glass

• the ice is more dense than the glass

Answer explanation

Ice cubes float because they are less dense than water. The correct choice is that the water is more dense than the ice cubes, allowing the ice to remain on the surface.

Water has a specific heat of 4184 J/KgºC.  Wood has a specific heat of 1760 J/KgºC.  What material needs more energy to raise the temperature 1ºC

• Wood

• Water

• Both are the same

Answer explanation

Water requires more energy to raise its temperature by 1ºC because it has a higher specific heat (4184 J/KgºC) compared to wood (1760 J/KgºC). Therefore, the correct answer is Water.

What is the meaning of adhesion?

• The amount of heat needed to raise the temperature of one gram of a substance by one degree Celsius

• The attraction of molecules for other molecules of a different kind

• The attraction of molecules for other molecules of the same kind

• The mass per unit volume of a substance

Answer explanation

Adhesion refers to the attraction of molecules for other molecules of a different kind, distinguishing it from cohesion, which is the attraction between similar molecules.

Why is water an excellent solvent?

• It has a high heat capacity

• It is less dense as a solid than as a liquid

• It has cohesive and adhesive properties

• It has the unique ability to dissolve many polar and ionic substances

Answer explanation

Water's unique ability to dissolve many polar and ionic substances makes it an excellent solvent. Its polar nature allows it to interact with and separate charged particles, facilitating chemical reactions.

Tags

NGSS.HS-ESS2-5

What is the unique property of water that allows ice to float in liquid water?

• High heat capacity

• Cohesive and adhesive properties

• Less dense as a solid than as a liquid

• High heat of vaporization

Answer explanation

The unique property of water that allows ice to float is that it is less dense as a solid than as a liquid. This means ice occupies more volume and is lighter than the liquid water, enabling it to float.

Why does water have high heat of vaporization?

• It is less dense as a solid than as a liquid

• It has cohesive and adhesive properties

• It takes a lot of energy to change one gram of a liquid substance to a gas at constant temperature

• It is an excellent solvent

Answer explanation

Water has a high heat of vaporization because it requires a significant amount of energy to convert one gram of liquid water into vapor at a constant temperature, due to strong hydrogen bonds between water molecules.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4