Chapter 2: Chemistry Of Life

Question 1

Matter

Answer 1

Anything that has mass and occupies space.

Question 2

Chemistry

Answer 2

The study of matter and its interactions.

Question 3

Atom

Answer 3

The smallest unit of matter that still retains its individual properties.

Question 4

Subatomic particles: list and describe

Answer 4

Proton:

Positively charged particle residing in the atomic nucleus.

Neutron:

Neutrally charged particle that is slightly larger than & paired w/ the Proton.

Electron:

Smallest particles that are negatively charged and surround the atomic nucleus.

Question 5

Describe the number of protons, electrons & neutrons found in an atom.

Answer 5

The number of positively charged protons are EQUAL to the number of negatively charged electrons.

Therefore, ALL ATOMS ARE ELECTRICALLY NEUTRAL.

The number of neutrons do not have to match.

Question 6

Describe the structure of an electron shell

Answer 6

Electron shells are regions where electrons are likely to be.

The 1st shell: Up 2 electrons

The 2nd shell: Up to 8 electrons

The 3rd shell: Up to 18, but satisfied at 8

Question 7

Element

Answer 7

A substance composed of one or more IDENTICAL atoms.

Elements CAN NOT be broken down into simpler substances by chemical means.

Question 8

Atomic Number

Answer 8

The number of protons contained in an element.

Question 9

Mass Number

Answer 9

The total of protons & neutrons in an element.

Question 10

Isotopes

Answer 10

Isotopes occur when an element contains more or less neutrons than listed in its Mass Number.

Question 11

Radioisotopes

Answer 11

Isotopes that have high energy & are unstable.

They release energy thru radiation to achieve a more stable form.

Question 12

Mixture

Answer 12

The physical combining of two or more elements, in which the chemical nature of the elements do not change.

The atoms retain their original properties and can be separated.

Question 13

Molecule

Answer 13

Two or more atoms that are combined by chemical bonds.

W/R to chemical bonds, the atoms are CHANGED chemically.

Can only be separated chemically.

Question 14

Mixture type: Suspension

Answer 14

A liquid mixed w/ a solid. The solid particles are usually visible (cloudy/opaque characteristics) and tend to settle in the bottom.

Ex. Blood

Question 15

Mixture type: Colloid

Answer 15

Appear opaque, but solids are not visible. Due to the solid particles small size, the do not settle out of the mixture.

Ex. Milk

Question 16

Mixture type: Solution

Answer 16

A solid, liquid or gas that is mixed with a liquid (usually h2o).

A solution is translucent b/c one substance dissolves in the other

Question 17

Solute vs Solvent

Answer 17

A solute is the substance that dissolves, and the substance in which the solute dissolves in is the solvent.

—-The degree to which a solute dissolves is its solubility.

—-The amount of solute included in a solution is the concentration.

h2o is the most important solvent in the human body.

A solution is still a mixture and does not change the solute or solvent chemically*

Ex. Simple Syrup (sugar is the solute, water is the solvent)

Question 18

Concenteation % ex:

10g of salt in 90mL h2o

30g of salt in 70mL h2o

Answer 18

10% salt solution

30% salt solution

Question 19

Chemical bond

Answer 19

An energy relationship between atoms, or an attractive force.

It is not a physical structure.

Question 20

Molecule vs Compound

Answer 20

All compounds are molecules, but not all molecules are compounds

Molecules form when two or more atoms are chemically bonded.

Molecules can have only the atoms from the element as in elemental molecules, or atoms from different elements.

Compounds are substances that form when TWO OR MORE ELEMENTS CHEMICALLY BOND.

Question 21

In general, how do chemical bonds form?

Answer 21

Chemical bonds form when the electrons in the valance shell of atoms interact.

Question 22

What do Valance electrons determine?

Answer 22

1.) how an atom interacts with other atoms.

2.) whether it will form a bond w/ a specific atom.

Question 23

Octet rule

Answer 23

The atoms relevant to physiology follow the octet rule, which states, an atom is most stable when it has 8 electrons in its valance shell.

Question 24

Duet rule

Answer 24

An exception to the octet rule pertains to atoms with 5 or less electrons.

Such atoms are more stable with only their first e- shell filled, which only holds 2 e-

Question 25

Chemical bonds & the disposition of valance electrons

Answer 25

A chemical bond alters the atom’s valance electrons. The bond allows reactive atoms to obey the octet/duet rule. The valance electrons are either: 1.) Transferred from one atom to another forming an Ionic Bond. 2.) Shared between two or more atoms, forming a Covalent Bond.

Question 26

Ionic bond

Answer 26

Bonds that result when an e- is transferred between a metal and a non-metal atom. Metals will *only* bond with a non-metal via an Ionic bond.

Question 27

How does Ionic bonding change the charge in an atom?

Answer 27

Adding or reducing e- in the valance shell results in the number of e- changing vs the number of protons present, and thus the overall charge in the atom. An atom with a positive charge is a Cation. An atom with a negative charge is a Anion. The attraction between the Cation and the Anion results in the formation of an Ionic Bond.

Question 28

Covalent Bonds

Answer 28

The STRONGEST CHEMICAL BONDS: Occurs when two or more NON-METAL atoms share electrons to fulfill the octet or duet rule.

Question 29

Single, Double & Triple Covalent Bonds

Answer 29

Single: one PAIR of e- is shared Double: two pair of e- are shared Triple: three pair of e- are shared *All bonds are made to total 8 *shared* valance e-

Question 30

Non-polar covalent

Answer 30

The electrons are shared equally.

Question 31

Polar covalent bond

Answer 31

The electrons are shared unequally. The e- are attracted more to one pole, or side of a compound.

Question 32

Electronegativity

Answer 32

All protons to some extent attract electrons. The more electronegative an element is, the more strongly it attracts electrons, and more likely that they will pull electrons away from less electronegative elements. Electronegativity increases from bottom left to top right of the periodic table, with Fluorine being the most electronegative. * The electronegativity of most metals is so low that they freely give up e-, which is why they cannot participate in covalent bonding.

Question 33

Non-polar Molecules

Answer 33

Molecules in which non-polar bonds predominate. When two non-metals in a molecule have identical or near identical electronegatives, they both tug on the e- w/the same force and the e- are shared equally (non-polar covalent bond).

Question 34

The 3 situations in which Non-polar Molecules occur:

Answer 34

1.) The atoms sharing the e- are of the same element. Identical atoms = Identical electronegatives 2.) The arrangement of the atoms makes one atom unable to pull more strongly than another atom. Electronegativity isn’t the only factor that influences how e- are shared, the arrangement of atoms is equally important. 3.) The bond is between Carbon & Hydrogen

Question 35

Polar Molecules

Answer 35

Molecules of compounds that contain primarily polar bonds. Polar bonds occur when nonmetals of different electronegativity interact, resulting in an unequal sharing of e- Stronger e- attraction will give that atom a partial negative charge. The other atom that has the lesser share of e- will have a partial positive charge. Molecules w/ these partially positive and negative ends are known as a *dipole* *As a whole though, polar molecules generally have an equal number of protons and electrons, and are thus electrically neutral*

Question 36

Hydrogen bonds and why they are different from ionic or covalent bonds

Answer 36

Not true bonds because e- are not transferred or shared. Also forms between compounds/polar molecules instead of atoms or ions. Rather, the partial polar charges act in a similar way to ions, in that they form weak attractions between the partial positive & partial negative poles of other compounds (polar molecules).

Question 37

Surface tension

Answer 37

Occurs because of hydrogen bonding. When air and water meet, the polar water molecules are more strongly attracted to one another than the Non-polar air molecules. This mutual attraction causes the water molecules to cluster together and form hydrogen bonds. Each water molecule can form up to 4 hydrogen bonds. W w no