Question

1. which element in water has greater electronegativity?

a. hydrogen
b. oxygen
c. both have the same
d. none of the above

1. which property of water is responsible for surface tension?

a. polarity
b. cohesion between molecules
c. density
d. temperature

1. the angle between the two hydrogen atoms in a water molecule is

a. 45°
b. 60°
c. 104.5°
d. 180°

1. the hydrologic cycle is powered by

a. ocean currents
b. the suns energy
c. earths rotation
d. gravity only

1. which process changes water from liquid to vapor?

a. condensation
b. evaporation
c. precipitation
d. infiltration

1. clouds form mainly due to

a. precipitation
b. condensation of water vapor
c. freezing of water
d. evaporation from soil

1. water returning to earths surface as rain or snow is called

a. evaporation
b. condensation
c. precipitation
d. transpiration

Explanation:

• Question 6: Oxygen has a higher electronegativity than hydrogen. Electronegativity is the ability of an atom to attract electrons. Oxygen's electronegativity value is approximately 3.44, while hydrogen's is about 2.20.
• Question 7: Cohesion between water molecules (due to hydrogen bonding) causes surface tension. Surface tension is the tendency of a liquid surface to resist external force.
• Question 8: The bond - angle between the two hydrogen atoms in a water molecule (\(H_2O\)) is \(104.5^{\circ}\) because of the bent molecular geometry (due to the two lone pairs on the oxygen atom).
• Question 9: The hydrologic cycle (water cycle) is powered by the Sun's energy. The Sun causes evaporation of water from oceans, lakes, etc.
• Question 10: Evaporation is the process that changes water from liquid to vapor. For example, water in a puddle evaporates under sunlight.
• Question 11: Clouds form mainly due to the condensation of water vapor. When warm, moist air rises and cools, the water vapor condenses into tiny droplets.
• Question 12: Water returning to Earth's surface as rain or snow is called precipitation. It is a key part of the water cycle.

Answer:

1. B. Oxygen
2. B. Cohesion between molecules
3. C. \(104.5^{\circ}\)
4. B. The Sun's energy
5. B. Evaporation
6. B. Condensation of water vapor
7. C. Precipitation