Chapter 2- Essential Chemistry For Biology Flashcards Preview

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Flashcards in Chapter 2- Essential Chemistry For Biology Deck (56):
1

Matter

Anything that occupies space and has mass.

2

3 physical states of matter

Solid
Liquid
Gas

3

Element

A substance that cannot be broken down into other substances by chemical reactions

4

Trace elements

Required in only very small amounts and it's essential for life.

Example: iodine deficiency causes goiter
-fluorine is added to products and drinking water to help maintain healthy bones and teeth.

5

Atom

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

6

Describe the structure of an atom: subatomic particles
Size
Charge
Location in the atom

Subatomic particles:
Proton + charged
Electron - charged
Neuron: electrically neutral

When the atom has an equal number of protons and electrons: net electrical charge is zero and atom is neutral.

Location: most atoms have protons and neutrons packed tightly into the nucleus.

7

Proton

+

8

Electron

-

9

Neutron

Electrically neutral

10

Atomic number

Number of protons in each atom of an element.

11

Mass number

The sum of the number of protons and neutrons in its nucleus.

12

Atomic mass

The total mass of an atom. Number under the element symbol

13

Isotope

A variant form of an atom. Different isotopes of an element have the same number of protons and electrons but different numbers of neutrons.

14

Radioactive Isotope

Nucleus decays spontaneously giving off particles and energy.

15

Chemical bond

an attraction between two atoms resulting from a sharing out outer-shell electrons or the presence of opposite charges on the atoms.

16

Ion

atoms or molecules that are electrically charged as a result of gaining or losing an electron.

17

Ionic bond

attraction between two ions with opposite electrical charges. the electrical attraction of the opposite charges holds the ions together.

18

covalent bond

two atoms share one or more pairs of electrons.

19

molecule

a group of two or more atoms held together by covalent bonds.

20

polar molecule

one with an uneven distribution of charge.

21

hydrogen bond

the polarity of water results in weak electrical attractions between neighboring water molecules.

22

ionic compound

Are Balanced. Table salt is an example of an ionic compound. Sodium and chlorine ions come together to form sodium chloride, or NaCl.

23

chemical reaction

rearranging of molecules by breaking existing chemical bonds and forming new ones. Hydrogen peroxide on a cut.

24

reactant

a starting material in a chemical reaction.

25

products

the end materials

26

cohesion

the attraction between molecules of the same kind

27

surface tension

measure of how difficult it is to stretch or break the surface of a liquid.

28

electron shell

the outside part of an atom around the atomic nucleus. It is a group of atomic orbitals with the same value of the principal quantum number n. Electron shells have one or more electron subshells, or sublevels.

29

Valence shell

The valence shell is the outermost shell of an atom. It is usually (and misleadingly) said that the electrons in this shell make up its valence electrons, that is, the electrons that determine how the atom behaves in chemical reactions.

30

valence electron

an electron that is associated with an atom, and that can participate in the formation of a chemical bond; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.

31

adhesion

The force of attraction between unlike molecules, or the attraction between the surfaces of contacting bodies. (cell biology) The binding of a cell to another cell, or a cell to a surface, via specific cell adhesion molecules

32

of the 25 elements essential for life, which ones are the most abundant in living matter?

oxygen
carbon
hydrogen
nitrogen

33

heat

Heat is the form of energy that is transferred between two substances at different temperatures. The direction of energy flow is from the substance of higher temperature to the substance of lower temperature.

34

temperature

refers to how hot or cold something is---a measure of the average kinetic energy of the particles in an object

35

solution

liquid consisting of a homogenous mixture of two or more substances.

36

solvent

the dissolving agent

37

solute

dissolved substance

38

aqueous solution

when water is the solvent the result is an aqueous solution

39

acid

a chemical compound that releases H+ to a solution

One example of a strong acid is hydrochloric acid (HCl), the acid in your stomach that aids in digestion of food.

40

base

a compound that accepts H+ and removes them from solution

41

pH

a measure of how acidic/basic water is.

42

pH Scale

describe the acidity of a solution- a measure of the hydrogen ion (H+) concentration in a solution. Scales ranges from 0(most acidic) to 14(more basic)

43

Buffers

a chemical substance that resists changes in pH by accepting hydrogen ions from or donating hydrogen ions to solutions.

44

Neutral pH

A substance that is neither acidic nor basic is neutral

45

neutral solution

a solution which has a pH of 7, so it's neither acidic (pH7), but right in the middle, or "neutral".

46

Atomic symbol for Hydrogen| 1 |
| H |
|1.00798|
give: how many protons
neutrons
electrons

protons: 1
neutrons:0
electrons:1

47

Maximum number of electrons that may occupy an elements first and second shells.

first shell max: 2
second shell max: 8
third shell max: 18

48

How do you determine valence electrons and how many covalent bonds it can make?

To find the valence electrons in an atom, identify what group the element is in. An element in group 1A has 1 valence electron.

example for covalent bond: O=C=O or F--F

49

how does a neutral atom become an ion?

it gains or loses one or more electrons

50

whats the difference between ionic bonds and covalent bonds?

Ionic bonds form when one atom donates or TRANSFERS valence electrons to another atom.
Covalent bonds form when two or more atoms SHARE valence electrons.

51

types of molecules capable of hydrogen bonding

The hydrogen acceptor is the neighboring electronegative ion or molecule, and must posses a lone electron pair in order to form a hydrogen bond.

52

how is hydrogen bonds different from ionic and covalent bonds?

Hydrogen bonds are intermolecular forces; covalent and ionic bonds are intramolecular forces.

53

explain why ice floats on water

Ice is less dense than liquid water because the more stable hydrogen bonds lock the molecules into a spacious crystal.

a chunk of ice floats because it is less dense than the liquid water in which it is floating. floating ice is a consequence of hydrogen bonds in liquid water, those in solid ice last longer, with each molecule bonded to four neighbors.

54

predict what types of compounds can be dissolved in water

polar molecules like sugars, salts, ect.

55

interpret pH values and determine how much or less acidic is sugar vs. lemon juice

sugar more basic
lemon is acidic

56

how does a buffer able to maintain the pH of a solution constant despite addition of acid or base to the solution.

If you add a strong acid like hydrochloric acid (HCl) to a buffered solution, there will suddenly be an excess of H+ ions from dissociation of the HCl. The buffers in the solution will respond by binding these excess H+ ions to re-form the weak acid, using up the excess H+ ions so that the pH can remain around the same value despite the addition of an acid.