Khan Academy - Chemistry of Life NOTES

Why is water considered essential to life?

Water is essential to life because all significant biological processes in the body depend on it and occur within it.

What is the approximate percentage of water in the human body?

The human body is approximately 60% to 70% water.

What are the components of a water molecule?

A water molecule is made up of one oxygen atom and two hydrogen atoms (H2O).

What type of bond connects the oxygen and hydrogen atoms in a water molecule?

The oxygen and hydrogen atoms in a water molecule are connected by covalent bonds.

What shape does a water molecule take due to the lone electron pairs on oxygen?

The oxygen molecule has a tetrahedral shape due to the repulsion of lone electron pairs.

What is the electronegativity of oxygen compared to hydrogen?

Oxygen is much more electronegative than hydrogen, meaning it attracts electrons more strongly.

What term is used to describe the partial charges in a water molecule?

The Greek letter delta (δ) is used to signify partial charges in a water molecule.

What type of bond forms between the different water molecules?

Hydrogen bonds form between different water molecules.

What properties of water are attributed to hydrogen bonding?

Hydrogen bonding contributes to water's ability to regulate temperature, evaporative cooling, surface tension, adhesion, cohesion, and its role as a solvent.

Why do lakes not freeze over completely during winter?

The unique properties of water, including hydrogen bonding, prevent lakes from freezing entirely.