Chapter 2: The Chemical Context Of Life

Question 1

Define Matter

Answer 1

Anything that has mass and takes up space.

Question 2

Matter is made up of _____.

Answer 2

Elements

Question 3

Define Element

Answer 3

Any substance that cannot be broken down to any other substance by chemical reactions.

Question 4

Define Compound

Answer 4

A substance consisting of two or more different elements combined in a fixed ratio.

Question 5

Of the 92 natural elements, about 20-25% are _____.

Answer 5

Essential Elements

Question 6

Define Essential Elements

Answer 6

A chemical element required for an organism to survive, grow, and reproduce. SGR

Question 7

How many elements do humans need and how many elements do plants need?

Answer 7

Humans: 25

Plants: 17

Question 8

What are the 4 elements that make up 96% of living matter?

Answer 8

Oxygen, Carbon, Hydrogen, and Nitrogen. OCHN

Question 9

Define Trace Elements

Answer 9

An element necessary for life but required in extremely minute amounts.

Question 10

What is an example of a trace element?

Answer 10

Iron

Question 11

What is caused by an iodine deficiency in a diet?

Answer 11

It causes the thyroid gland to grow to an abnormal size, a condition called goiter.

Question 12

What is an example of a naturally occurring element that is toxic to humans?

Answer 12

Arsenic

Question 13

What is an example of a community that has adapted to an environment containing toxic elements?

Answer 13

Serpentine Plant Communities

Question 14

Define Atom

Answer 14

The smallest unit of matter that retains the properties of an element.

Question 15

What are the 3 kinds of subatomic particles?

Answer 15

Electrons-Neutrons-Protons

Question 16

Define Neutron

Answer 16

A nerve cell; the fundamental unit of the nervous system, having structure and properties that allow it to conduct signals by taking advantage of the electrical charge across its plasma membrane.

Question 17

Define Proton

Answer 17

A subatomic particle with a single positive electrical charge, with a mass of about 1.7x10^-24g, found in the nucleus of an atom.

Question 18

Define Electron

Answer 18

A subatomic particle with a single electrical charge and a mass oof about 1/2000 that of a neutron or proton. One or more electrons move around the nucleus of an atom.

Question 19

Define Atomic Nucleus

Answer 19

An atom’s dense central core, containing protons and neutrons.

Question 20

Define Dalton

Answer 20

A measure of mass for atoms and subatomic particles; the same as the atomic mass unit, or amu.

Question 21

Define Atomic Number

Answer 21

The number of protons in the nucleus of an atom, unique for each element and designated by a subscript.

Question 22

Define Mass Number

Answer 22

The total number of protons and neutrons in an atom’s nucleus.

Question 23

Where do the mass number and atomic number of an atom go?

Answer 23

Mass Number: Top LEFT

Atomic Number: Bottom LEFT

Question 24

Define Atomic Mass

Answer 24

The total mass of an atom, numerically equivalent to the mass in grams of 1 mole of the atom. (For an element with more than one isotope, the atomic mass is the average mass of the naturally occurring isotopes, weighed by their abundance).

Question 25

Define Isotope

Answer 25

One of several atomic forms of an element, each with the same number of protons but a different number of neutrons, thus differing in atomic mass.

Question 26

Do isotopes behave identically in chemical reactions?

Answer 26

Yes

Question 27

Define Radioactive Isotope

Answer 27

An isotope that is unstable; the nucleus decays spontaneously, giving off detectable particles and energy.

Question 28

Define Half-Life

Answer 28

The amount of time it takes for 50% of a sample of a radioactive isotope is to decay.

Question 29

Each radioactive isotope has a characteristic half-life that is NOT affected by _____, _____, or any other environmental factors.

Answer 29

Temperature-Pressure

Question 30

Define Radiometric Dating

Answer 30

A method for determining the absolute age of rocks and fossils, based on the half-life off radioactive isotopes.

Question 31

Which of the subatomic particles are involved in chemical reactions?

Answer 31

Electrons

Question 32

Define Energy

Answer 32

The capacity to cause change, especially to do work (to move matter against an opposing force).

Question 33

Define Potential Energy

Answer 33

The energy that matter possesses as a result of its location or spatial arrangement (structure).

Question 34

The more distant an electron is from the nucleus, the _____ its potential energy.

Answer 34

Greater

Question 35

Define Electron Shells

Answer 35

An energy level of electrons at a characteristic average distance from the nucleus of an atom.

Question 36

How many electrons can each shell hold? (Going from shell closest to shell that’s farthest)

Answer 36

2-8-8

Question 37

Define Valence Electrons

Answer 37

An electron in the outermost electron shell.

Question 38

Define Valence Shell

Answer 38

The outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom.

Question 39

Can atoms with filled electron shells partake in chemical reactions?

Answer 39

No, they are inert.

Question 40

Define Orbital

Answer 40

The 3D space where an electron is found 90% of the time.

Question 41

Define Chemical Bonds

Answer 41

An attraction between two atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells.

Question 42

Define Covalent Bonds

Answer 42

A type of strong chemical bond in which two atoms share one or more pairs of valence electrons.

Question 43

Define Molecule

Answer 43

Two or more atoms held together by covalent bonds.

Question 44

Define Single Bond

Answer 44

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

Question 45

Define Double Bond

Answer 45

A double covalent bond; the sharing of two pairs of valence electrons by two atoms.

Question 46

Define Valence

Answer 46

The bonding capacity of a given atom; the number of covalent bonds that an atom can form, which usually equals the number of unpaired electrons in its outermost (valence) shell.

Question 47

Define Electronegativity

Answer 47

The attraction of a given atom for the electrons of a covalent bond.

Question 48

Define Non-Polar Covalent Bond

Answer 48

A type of covalent bond in which electrons are shared equally between two atoms of similar Electronegativity.

Question 49

Define Polar-Covalent Bond

Answer 49

A covalent bond between atoms that differ in Electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.

Question 50

Define Ions

Answer 50

An atom or group of atoms that has gained or lost one or more electrons, thus acquiring a charge.

Question 51

Define Cation

Answer 51

A positively charged ion.

Question 52

Define Anion

Answer 52

A negatively charged ion.

Question 53

Define Ionic Bond

Answer 53

A chemical bond resulting from the formation of an ionic bond; also called a salt.

Question 54

Define Ionic Compound

Answer 54

A compound resulting from the formation of an ionic bond; also called a salt.

Question 55

Does an ionic compound consist of molecules?

Answer 55

No

Question 56

Define Hydrogen Bond

Answer 56

A type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule or in another region of the same molecule.

Question 57

Define van der Waals interactions

Answer 57

Weak attractions between molecules or parts of molecules that result from transient local partial charges.

Question 58

Define Chemical Reactions

Answer 58

The making and breaking of chemical bonds, leading to changes in the composition of matter.

Question 59

Define Reactants

Answer 59

A starting material in a chemical reaction.

Question 60

Define Product

Answer 60

A material resulting from a chemical reaction.

Question 61

Are atoms destroyed/created in a chemical reaction or rearranged?

Answer 61

They are rearranged

Question 62

What is a factor that impacts the rate of a reaction?

Answer 62

The concentration of reactants.

Question 63

The greater the concentration of reactant molecules, the _____ frequently they collide with one another and have an opportunity to react and form products.

Answer 63

More

Question 64

Define Chemical Equilibrium

Answer 64

In a chemical reaction, the state in which the rate of the forward reaction equals the rate of the reverse reaction, so that the relative concentrations of the reactants and products do not change with time.

Question 65

How can the movement of electrons be described?

Answer 65

They are constantly moving.

Question 66

What is the most abundant element?

Answer 66

Carbon

Question 67

In radioactive decay, what happens to the neutrons?

Answer 67

They decay into protons

Question 68

How are tumors detected with radioactive glucose?

Answer 68

Cancer cells require more energy than normal cells; so, the glucose goes to the cells that require more energy.

Question 69

What are the maximum number of electron shells that an atom can have?

Answer 69

3

Question 70

What happens to electrons when light is shined on an atom?

Answer 70

When light is shined, the electrons in the lower shells get promoted to a higher level; however, it doesn’t stay that way.

Question 71

Do atoms with the same valence electron on the same valence shell show similar behavior?

Answer 71

Yes

Question 72

How many electrons can each orbit hold?

Answer 72

2

Question 73

Are H-Bonds present in DNA?

Answer 73

Yes