Properties of Life and Chemical Context of Life

These flashcards cover the essential concepts of life and the chemical context of life, including matter, elements, compounds, essential elements, isotopes, chemical bonds, and the properties of water.

What defines matter and what are its components?

Matter is anything that takes up space and has mass. It is composed of atoms, which are the smallest units of matter.

What is an atom?

An atom is the smallest unit of matter that retains the properties of an element.

Define an element.

An element is a substance that cannot be broken down to other substances by chemical reactions.

What is a compound?

A compound is a substance composed of two or more different elements in a fixed ratio.

What percentage of natural elements are essential for life?

About 20–25% of the 92 natural elements are required for life.

Which elements make up 96% of living matter?

Carbon, hydrogen, oxygen, and nitrogen.

What are trace elements?

Trace elements are those required by an organism in only minute quantities.

Define isotopes.

Isotopes are atoms of an element that differ in the number of neutrons.

What is a covalent bond?

A covalent bond is the sharing of a pair of valence electrons by two atoms.

What distinguishes a polar covalent bond from a nonpolar covalent bond?

In a polar covalent bond, one atom is more electronegative and the electrons are not shared equally, while in a nonpolar covalent bond, the electrons are shared equally.

What characterizes an ionic bond?

Ionic bonds form when atoms strip electrons from their bonding partners, resulting in oppositely charged ions that attract each other.

Explain the concept of hydrogen bonds.

A hydrogen bond occurs when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom.

What are weak chemical interactions and their importance?

Weak interactions, such as hydrogen bonds and Van der Waals interactions, contribute to the structure and function of large biological molecules.

What is the role of valence electrons in determining chemical behavior?

The number of valence electrons determines the chemical behavior of an atom.

What are the four emergent properties of water?

1. Water can bond with many molecules; cohesion or adhesion. 2. High boiling point and low freezing point. 3. Expansion when freezing; density difference. 4. Universal solvent.

Define pH in relation to hydrogen ion concentration.

pH is a measure of hydrogen ion concentration on a scale of 0-14, where acids increase H+ concentration, and bases decrease it.

What happens during dissociation of water?

Water dissociates into hydrogen ions (H+) and hydroxide ions (OH-), with a neutral balance at pH 7.