AP Bio, Sem A - Unit 1: Nature of life

¹³C and ¹⁴C are isotopes of ¹²C, which has 6 electrons, 6 protons, and 6 neutrons. What is the arrangement of subatomic particles in ¹⁴C?

• 6 electrons, 7 protons, and 6 neutrons

• 6 electrons, 7 protons, and 8 neutrons

• 6 electrons, 6 protons, and 8 neutrons

Sodium has the atomic number 11. How many electrons are in a sodium ion, which has the symbol Na⁺?

• 10

• 11

• 12

Which is the definition of adhesion?

• The property in which water molecules stick to one another tightly.

• The property in which water molecules easily evaporate into a gas.

• The property in which water molecules are attracted to other polar substances.

Between which two atoms of water are hydrogen bonds are formed?

• between the hydrogen atom of one water molecule and the oxygen atom of another

• between the hydrogen atoms of two water molecules

• between the oxygen atoms of two water molecules

Frozen water (ice) has less density than liquid water.
How does this property of water affect life on earth?

• Ice floats on the surface, sustaining life at the bottom of lakes and oceans.

• Ice floats on the surface, helping animals migrate over lakes and bays.

• Ice floats on the surface, maintaining sub–zero temperatures at the bottom of lakes and oceans.

Which best defines cohesion?

• Cohesion is caused by polar water molecules attracting each other.

• Cohesion is caused by polar water molecules repelling each other.

• Cohesion is caused by polar water molecules repelling and not mixing with non–polar molecules.

When trees transpire, releasing gaseous water into the atmosphere, they can absorb heat from their environment and cool it down. What property of water is responsible for this activity?

• high heat capacity

• high heat of vaporization

• adhesion

Which statement correctly explains the polarity of the water molecule?

• The hydrogen end of the molecule has a partial negative charge and the oxygen end has a partial positive charge.

• The oxygen end of the molecule has a partial negative charge and the hydrogen end has a partial positive charge.

• Both ends of the molecule have a partial negative charge, which attracts the other water molecule towards itself.

What is the amount of heat required to raise the temperature of water referred to as?

• heat of vaporization

• specific heat

• heat of combustion

Which property of water makes it helpful to use in car radiators?

• Water can climb up the sides of a tube.

• Water is a universal solvent.

• Water takes longer to heat and cool down than other liquids.