Biology 111: General Chemistry and Water Properties

What is matter?

Anything that takes up volume and has mass.

What is the difference between mass and weight?

Mass is the measure of the amount of matter in an object, while weight is how strongly the object is pulled by gravity.

How many naturally occurring elements are there?

There are 92 naturally occurring elements.

What are the six essential elements for life, often referred to as 'CHNOPS'?

Carbon (C), Hydrogen (H), Nitrogen (N), Oxygen (O), Phosphorus (P), and Sulfur (S).

What role does Iron (Fe) play in living organisms?

It is the central atom of hemoglobin protein, which bonds to O2.

What is a molecule?

Two or more atoms combined in a fixed ratio, such as NaCl.

What is the definition of a compound?

A molecule composed of two or more different elements.

What are the three sub-atomic particles that make up an atom?

Protons (p+), Electrons (e-), and Neutrons (n).

What determines the charge of an atom?

The balance between the number of protons (positive charge) and electrons (negative charge).

What is the atomic number?

The number of protons in an atom of a particular element.

What is the mass number?

The total number of protons and neutrons in an atom.

What is the maximum number of electrons in the first three shells of an atom?

2 in the first shell, 8 in the second shell, and 8 in the third shell.

What happens to an electron when it becomes 'excited'?

It may jump to the next outer shell but will return to its original shell unless it escapes the atom.

What is an ionic bond?

A bond formed when one atom donates an electron to another atom, resulting in oppositely charged ions that attract each other.

What is the goal of atoms in forming bonds?

To achieve stability by having a complete outer electron shell, usually with 8 electrons.

What is the significance of trace elements in biology?

They are required for life in extremely minute quantities.

What is the role of Magnesium (Mg) in living organisms?

It is the central atom of chlorophyll, essential for photosynthesis.

What is the role of Calcium (Ca) in the body?

It is required for muscle contraction.

What is Carbon Dioxide (CO2)?

A colorless and odorless gas that is a product of respiration and combustion.

What is Ozone (O3) and its environmental significance?

An atmospheric gas that filters out harmful ultraviolet radiation.

What are CFCs and their impact on the environment?

Chlorofluorocarbons that disrupt the ozone layer, leading to environmental problems.

How do atoms achieve stability through ionic bonding?

By transferring electrons to complete their outer electron shells.

What is the structure of a carbon atom?

It has 6 protons, 6 neutrons, and 6 electrons arranged with 2 in the inner shell and 4 in the outer shell.

What is the significance of the 'Sphere of Probability'?

It describes the regions where electrons are likely to be found around the nucleus.

What is the relationship between atomic mass units (A.M.U.) and daltons?

1 A.M.U. is equivalent to 1 dalton.

What happens to an atom when it loses an electron?

It becomes a positively charged ion.

What is the mass number of Carbon-12 (12C)?

12

What is the atomic number of Carbon?

6

What defines an ion?

An ion has a different number of electrons compared to protons.

What is an isotope?

An isotope has the same atomic number but a different number of neutrons.

What is a radioactive isotope?

An unstable atom that spontaneously decays, emitting subatomic particles.

What is half-life?

The time required for half of a radioactive sample to decay.

How is geological dating achieved using isotopes?

By comparing the ratio of stable and radioactive isotopes to estimate the age of fossils.

What is the role of radioactive biological tracers?

They are used to trace biochemical reactions and locate substances in organisms.

What is a covalent bond?

A bond formed when two atoms share electrons to achieve stability.

What is the chemical structure of water (H2O)?

It consists of two hydrogen atoms covalently bonded to one oxygen atom.

Why is water considered a polar molecule?

Oxygen has a higher electronegativity, creating a partial negative charge at the oxygen end.

What are hydrogen bonds?

Weak attractions between the positive hydrogen of one water molecule and the negative oxygen of another.

What unique property does water exhibit when it freezes?

Water expands when frozen, causing ice to float.

What is cohesion in water?

The collective strength of hydrogen bonds that keeps water molecules together.

What is the pH scale used for?

To measure the acidity or alkalinity of a substance based on H+ ion concentration.

What is the pH of rainwater?

Approximately 5.6, which is mildly acidic.

What causes the mild acidity of rainwater?

The combination of water with atmospheric CO2 to form carbonic acid.

What is the ecological importance of mildly acidic rainwater?

It gradually breaks down local rock, contributing to soil formation.

What is industrial acid precipitation?

Rainwater that has been acidified by industrial contaminants, resulting in a lower pH.

What are the effects of industrial acid precipitation on oceans?

It increases ocean acidity, which can diminish coral populations.

What is the role of industrial scrubbers?

They reduce the acidity of substances released into the atmosphere.

What happens to soil particles washed into the sea?

They drop to the bottom and do not function as soil again.

How does water's expansion at freezing benefit aquatic life?

It provides insulation, allowing life to thrive beneath the ice.

What is the significance of surface tension in water?

It allows lightweight insects to walk on water due to strong hydrogen bonds.

What is the relationship between isotopes and chemical reactions?

Isotopes react chemically the same way as stable atoms due to similar electron configurations.

What occurs during the decay of Carbon-14 (14C)?

It loses a neutron to become Carbon-13 (13C) and eventually Carbon-12 (12C).