Structure, Polarity, and Hydrogen Bonding
True or False, Water’s hydrogen bonds are weak interactions that constantly break and reform
True, hydrogen bonds constantly break and reform
True or false, ice is denser than liquid water, which is why it floats.
False – ice is less dense than liquid water, which is why it floats
True or false, Hydrogen bonding occurs only in water molecules and nowhere else
False – hydrogen bonding occurs in other polar molecules too (e.g., ammonia, ethanol)
True or false, the high heat of vaporization of water helps animals cool themselves through sweating
True – evaporation of sweat absorbs heat energy, cooling the body
What is hydrogen bonding?
Hydrogen bonding is a weak attraction between the partially positive hydrogen atom of one molecule and the partially negative oxygen (or other electronegative atom) of another molecule.
Which property of water explains why coastal areas have moderate climates?
High specific heat
What bond occurs between the hydrogen of one water molecule and the oxygen of another?
Hydrogen Bond
Why is the density difference between ice and liquid water critical for aquatic life?
Because ice floats, liquid water remains beneath the ice in lakes and ponds, allowing aquatic life to survive winter.
If water molecules were nonpolar, how would it affect life on Earth?
If water were nonpolar, it could not dissolve salts or polar molecules, could not support hydrogen bonding, and many life-supporting processes (like nutrient transport and temperature regulation) would not be possible.
Name and give a short explanation for the seven properties of water
- Cohesion – water molecules stick to each other
- Adhesion – water molecules stick to other surfaces
- Surface Tension – hydrogen bonds at the surface create almost a “skin” on the water
- High Specific Heat – water resists temperature change
High Heat of Vaporization – takes a lot of energy to evaporate water
- Lower Density of Ice – ice floats because it is less dense than liquid water
- Universal Solvent – water dissolves many ionic and polar substances