chapter 2

Question 1

Atoms: the stuff of life

1. matter
2. energy

Answer 1

1. eg organisms, rocks
2. ability to do work
   - moving matter
   - heat, light, & chemical bonds

Question 2

elements:

Answer 2

a basic substances made of atoms that cannot be separated by chemical means into simpler substance
-example: pure oxygen, carbon, sodium

Question 3

periodic table:

Answer 3

(arrangement) 92 natural elements

Question 4

1. 8
2. oxygen
3. O
4. 15,9994

Answer 4

1. atomic #
2. element
3. symbol
4. atomic mass

Question 5

25 elements essential to life (3 of them):

Answer 5

1. bulk elements
   - eg. C,H,O,N
2. minerals
   - eg. Na, Mg, P, K, Ca
3. trace elements
   - eg. Fe, I

Question 6

atoms:

Answer 6

composed of 3 subatomic particles- 
- proton: + 
- neutron: 0 
- electron: - 
(small mass)

Question 7

atomic #

Answer 7

arranged on periodic table sequentially

Question 8

of protons:

Answer 8

number of electrons:

Is the atom electrically neutral?

Question 9

ion:

Answer 9

• net negative or positive charge

- hydrogen (H+), sodium (Na+), chloride (Cl-)

Question 10

3 chemical bonds:

Answer 10

1. diatomic- molecule with 2 atoms of the same element
   eg. oxygen (O2), nitrogen (N2)
2. compound- molecule with 2 or more different elements
   eg. nitric oxide (No), water (H2O)
3. molecule formula- Ch4 has 4 hydrogen atoms attached to one carbon atom

Question 11

electrons:
1. orbital
2. energy shell

Answer 11

1. each holds up 2 elements
2. energy shell
   diagram*

Question 12

orbits:

Answer 12

• # of orbits in a shell determines how many total electrons the shell can hold
• 1st energy shel- one orbital (# of electrons?)
• next 2 energy shell- 4 orbitals each (# of electrons?)
  diagram*

Question 13

valence shell:

1. insert
2. to fill

Answer 13

1. valance shell full so very stable
   eg. helium (He)
2. partially empty valence shell, atoms will share, steal or donate electrons

Question 14

electronegativity:

Answer 14

measure of an atom’s ability to attract electrons

Question 15

covalent bonds:

1. non-polar
2. polar

Answer 15

- forms when 2 atoms share electrons 
Non-polar:
1. nearly equal electronegativity 
2. will not interact with water 
3. methane (CH4) 
Polar:
1. different electronegativity 
2. interact with water 
3. water (H2O)

Question 16

ionic bonds:

Answer 16

1. donation (not shared)
2. often occur b/w atoms with nearly empty valence shell and nearly full valence shell
3. electronegativity at opposite ends of the spectrum
4. readily forms solutions
5. examples: calcium chloride(road salt), sodium chloride (table salt)

Question 17

hydrogen bonds:

Answer 17

1. opposite partial charge on adjacent molecules or within the same large molecule attract each other
2. hydrogen is usually the partially positive member
3. oxygen slightly negative
4. relatively weak comparent to covalent & ionic
   eg. H2O molecule

Question 18

case study:

1. cohesion
2. adhesion

Answer 18

- water essential to life 
Cohesion 
1. based on hydrogen bonding 
2. high surface tension that forms a "skin" strong enough to support small insects
Adhesion 
1. based on hydrogen bonding 
- cohesion & adhesion work together in capillary action 
eg. a flower 
- water comes from via roots
- exits through steam onto leaves

Question 19

universal solvent:

1. solution
2. hydrophilic
3. hydrophobic

Answer 19

solvent vs. solute 
1. aqueous solution: solvent is water 
2. water loving 
- substance readily dissolves in water 
polar covalent* 
3. water fearing
- substance doesn't dissolve 
eg. oil

Question 20

more properties of water:

Answer 20

1. ability to resist temperature changes
2. more heat needed to raise water’s temp. than other liquids
3. bodies heat & cool more slowly
4. evaporation: conversion of a liquid into vapor

Question 21

water expands when frozen:

1. ice floats

Answer 21

1. ice covering insulates water
2. lakes do not freeze from the bottom up
   - cells are prone to rupture when frozen
3. adaptations to make “antifreeze” or dehydration

Question 22

water in life’s process:

Answer 22

chemical reactions:

• chem. bonds break & new ones form
• starting materials are reactants
• products —> results of matter
• atoms are neither created nor destroyed

Question 23

acids & bonds:

Answer 23

• water can break apart into a hydrogen ion (H+) & a hydroxide ion (OH-)
• in a neutral solution, H+ = OH-
  1. acids:
• more H+ than OH-
• hydrochloric acid (HCL), sulfure acid (H2SO4)
  2. base: 2 ways
  1. add OH-
  2. absorb H+
• sodium hydroxide (NaOH)

Question 24

PH scale

Answer 24

• acidic solution Ph 7
• each unit is a 10-fold charge in H+ concentration
• Ph 4-10 times more acidic than Ph 5
• buffer systems are pairs of weak acids & bases that resist Ph changes
• your body is full of buffer systems- carbonic acid/ bicarbonate system
• maintains blood ~ 7.4

Question 25

bonds contain energy:

Answer 25

- break a bond: requires energy - make a bond: releases energy - triple bonds > double bonds > single bonds eg. more energy released for acetylene

Question 26

organic molecules:

Answer 26

- chemical compounds that contain both carbon and hydrogen - hydrocarbons consist almost entirely of carbon & hydrogen eg. CH4 - 4 types: 1. carbohydrates 2. lipids 3. proteins 4. nucleic acids

Question 27

dehydration synthesis:

Answer 27

take out H2O | diagram*

Question 28

hydrolysis:

Answer 28

add water back in to result break in bonds | diagram*

Question 29

carbohydrates:

Answer 29

- organic molecules that consist of carbon, hydrogen & oxygen - simple sugars 1. monosaccharides- most - same # of carbon atoms can be put together different to give very diff. molecules

Question 30

carbs | - simple sugars

Answer 30

- disaccarides: 1. 2 monosaccarides 2. sucrose= fructose + glucose 3. covalent bond (specifically a glycosidic bond) - oligosaccharides: 1. most common in plants 2. in animals, attach to proteins on the cell membrane involved ---> cell recognition 3. typically have a sweet flavor

Question 31

complex carbs:

Answer 31

- polysaccharides 1. cellulose- plant cell wall 2. chitin- exoskeleton of insects, cell wall of fungi - a polymer of glucose with an amine group attached 3. starch- plant energy storage 4. glycogen- animal & fungi energy storage - primary constituent of exoskeletons of crustaceans & insects

Question 32

lipids:

Answer 32

- hydrophobic (water fearing) - large areas with non polar c-c 7 c-h bond - stored in adipose tissue - several groups - triglycerides, sterols, waxes*

Question 33

triglycerides:

Answer 33

- saturated fatty acids have all single bonds b/w carbons eg. animal fat, solid - unsaturated fatty acids have at least 1 double bond b/w carbons eg. plant-derived, liquids, veg. oil - trans fat 1. man made 2. partially -hydrogenated 3. solid at room temp.