Question

Chapter 2 discusses three important properties of water: cohesiveness, temperature-stabilizing capacity, and general solvent. How is hydrogen bonding responsible for each?

Answer 1

Hydrogen bonding is one of the major factor that influence the properties of water.

Let us see all that properties you mentioned in question and how hydrogen bonding paly role in case-

1. Cohesion-

Because of the extensive hydrogen bonding in water, the molecules tend to stick to each other in a regular pattern. This phenomenon, called cohesion, is easily observed as you carefully overfill a glass with water and observe the water molecules holding together above the rim until gravity overtakes the hydrogen bonding and the water molecules spill down the side of the glass. Likewise, the cohesive property of water allows tall trees to bring water to their highest leaves from sources below ground.

2. Temperature-stabilizing capacity-

Once again hydrogen bonding is responsible for high temperature stabilizing capacity of water.

How Water Stabilizes Temperature

Water has a high specific heat, which means that it resists temperature changes when it absorbs or releases heat.

As a result of hydrogen bonding among water molecules, it takes a relatively large heat loss or gain for each 1 degree C change in temperature.

Hydrogen bonds must absorb heat to break, and they release heat when they form.

Much absorbed heat energy is used to disrupt hydrogen bonds before water molecules can move faster (increase temperature).

3. General solvent-

Water is a good solvent due to its polarity. The solvent properties of water are vital in biology, because many biochemical reactions take place only within aqueous solutions

When an ionic or polar compound enters water, it is surrounded by water molecules. The relatively small size of water molecules typically allows many water molecules to surround one molecule of solute. The partially negative dipoles of the water are attracted to positively charged components of the solute, and vice versa for the positive dipoles.

In general, ionic and polar substances such as acids, alcohols, and salts are easily soluble in water, and nonpolar substances such as fats and oils are not. Nonpolar molecules stay together in water because it is energetically more favorable for the water molecules to hydrogen bond to each other than to engage in van der Waals interactions with nonpolar molecules.