Biology Unit 2

What word describes when water is attracted to other substances?

• cohesion
• adhesion
• capillary action
• surface tension

What two elements make up water?

• Helium and oxygen
• Hydrogen and oxygen
• helium and carbon
• oxygen and carbon

Attractions between the negative Oxygen atom of one water molecule and the positive Hydrogen atom of another water molecule are called

• Covalent bonds
• Ionic bonds
• Polar bonds
• Hydrogen bonds

Why does ice float?

• As water freezes, it expands and its density decreases.
• As water freezes, it takes up more hydrogen from the atmosphere, causing it to have a greater buoyancy.
• As water freezes, air becomes trapped between the hydrogen bonds of water molecules.
• As water freezes, it takes up more oxygen from the atmosphere, causing it to have a greater buoyancy.

Which of the following is LEAST likely to dissolve in water?

• nonpolar fats and oils
• polar sugar molecules
• salt made of a positive sodium ion and a negative chloride ion
• all of the substances will dissolve easily in water

Large bodies of water, such as lakes and oceans, do not quickly fluctuate in temperature. What is the reason for this phenomenon?

• Water is an acid.
• Water is a versatile solvent.
• Water has a high heat capacity.
•  Water acts as a buffer.

The tightness across the surface of water that enables paper clips to float is ____________.

• adhesion
• capillary action
• surface tension
• polarity

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

What is the chemical symbol of water?

• H2O

• CO2

• O2

• N2

What is cohesion?

• The ability of a molecule to "stick" to itself

• The ability of a molecule to "stick" to other molecules

• Large amounts of energy are required to change the temperature of a substance

• A well-organized and efficient team