Chp 2 & 3 Chemistry and Molecules of Life

Question 1

What are the two polarnegative elements?

Answer 1

Oxygen and Nitrogen

Question 2

What are two most common non polar elements?

Answer 2

Carbon and Hydrogen

Question 3

Is CH polar?

Answer 3

No

Question 4

Is H2O polar

Answer 4

Yes, mucho polar

Question 5

Which macromolecules and molecules in general are hydrophobic?

Answer 5

Lipids especially, non polar bonds

Question 6

Which compounds are hydrophilic?

Answer 6

Ones with polar bonds.

Question 7

Ultimately, all the properties of organisms depend on ?

Answer 7

how atoms are arranged in molecules. how molecules are arranged in cells

Question 8

What is a compound?

Answer 8

A substance containing 2 or more elements in a fixed ratio

Question 9

What is an isotope?

Answer 9

Two atoms of an element thar differ in number of neutrons

Question 10

How is the atomic number determined?

Answer 10

number of protons in the nucleus

Question 11

How is atomic mass determined?

Answer 11

Number of protons and neutrons in atom

Question 12

What are valence electrons? What do they affect?

Answer 12

electrons on the outer most shell. They determine how the atom behaves (low/high energy)

Question 13

What is the valence of an element? What does this correspond to?

Answer 13

The number of electrons necessary to complete the outer shell. corresponds to the number of covalent bonds an element can form

Question 14

How many bonds can hydrogen form?

Answer 14

One

Question 15

What is a covalent bond?

Answer 15

they share electrons

Question 16

what is an ionic bond?

Answer 16

atoms strip electrons from bonding partners to stabilize both

Question 17

How does water affect ionic bonds?

Answer 17

It attracts the polarly charged atoms and disolves the compound.

Question 18

How is H2O charged?

Answer 18

Neutrally, but part is partially positively charged and part is partially negatively charged

Question 19

Four emergent properties of water contribute to its ability to support life on Earth. What are they?

Answer 19

Cohesive behavior
ability to moderate temperature
expansion upon freezing
versatility as a solvent

Question 20

Explain waters ability to be cohesive.

What is cohesion? How does it benefit earthlings?

Answer 20

Cohesion= tendency of molecules to stick together (hydrogen bonds)

• its benefits plants by helping water move against gravity when being delivered through plants
• helps in tear drainage
• surface tension

Question 21

Explain waters ability to moderate temperature. How does this impact earth and earthlings?

Answer 21

water can release or absorb a large amount of heat with only a slight change in temperature.
its good for eathlings because we are composed of water and so when its hot out we dont brun to death because it takes so much heat for water to change temperature

Question 22

Heat vs temperature

Answer 22

Heat: Measure of total kinetic energy to molecular motion.
Temperature: measures heat due to average kinetic energy of molecules

Question 23

Why does it take so long for water to heat up?

Answer 23

heat energy is used to break hydrogen bonds before it can begin making the molecules move fast enough

Question 24

why do ice cubes float in water?

Answer 24

Hydrogen bonds are more ordered when solid

Question 25

why is water expanding upon freezing important?

Answer 25

if ice sank, all bodies of water would eventually freeze solid

Question 26

what is a solvent

Answer 26

dissolving agent of a solution

Question 27

high or low ph donate H+

Answer 27

acid

Question 28

which ph accepts H+ ions?

Answer 28

bases

Question 29

what is a hydrocarbon?

Answer 29

a compound consisting only of carbons and hydrogens

Question 30

What is an isomer?

Answer 30

Same molecular formula but different structures and properties