water

Question 1

what happens in ionic bonding

Answer 1

-atoms recieve or donate electrons
-some lose and become positive anions
-some gain and become negative cations

Question 2

what holds ions together in bonding

Answer 2

ionic bonds

Question 3

what happens in covalent bonding

Answer 3

shared electrons
usually molecule produced is neutral
very strong covalent bonds

Question 4

what happens to some molecules in covalent bonding

Answer 4

they become slightly polarised

Question 5

how does polarity occur

Answer 5

the electron is not evenly shared so molecule is slightly negative and positive

Question 6

dipole

Answer 6

separation of charge in a molecule when the electrons in covalent bonds are not evenly shared

Question 7

whats a polar molecule

Answer 7

a molecule containing a dipole

Question 8

what are hydrogen bonds

Answer 8

weak electrostatic intermolecular bonds formed between polar molecules containing at least one hydrogen atom

Question 9

what molecules does polarity occur the most

Answer 9

molecules with one or more hydrogen atom

Question 10

what happens when ionic substances are put in water

Answer 10

they dissolve

Question 11

symbol for nitrate ion

(anion)

Answer 11

NO3-

Question 12

symbol for phosphate ions

(anion)

Answer 12

PO43-

Question 13

symbol for chloride ions

(anion)

Answer 13

CL-

Question 14

hydrogen carbonate ions symbol

(anion)

Answer 14

HCO3-

Question 15

function of nitrate ions

Answer 15

needed in plants for formation of amino acids and therefore proteins from products of PH and formation of DNA

Question 16

function of phosphate ions

Answer 16

for formation of ATP ADP DNA RNA

Question 17

function of chloride ions

Answer 17

needed in nerve impulses and many secretory systems

Question 18

function of hydrogen carbonate ions

Answer 18

buffering the blood to prevent it from becoming to acidic

Question 19

symbol for sodium ions

Answer 19

NA+

Question 20

symbol for calcium ions

Answer 20

CA2+

Question 21

symbol for hydrogen ions

Answer 21

H+

Question 22

symbol for magnesium ions

Answer 22

MG2+

Question 23

function of sodium ions

( cations)

Answer 23

needed for nerve impulses and secretory systems

Question 24

function of calcium ions

(cations)

Answer 24

needed for formation of calcium pectate for middle lamella between two cell walls in plants and bone formation and muscle contraction in animals

Question 25

function of hydrogen ions (cations)

Answer 25

needed in cellular respiration and PH and systems to maintain PH balance

Question 26

function of magnesium ions (cations)

Answer 26

needed for production of chlorophyll in plants

Question 27

why is water polar

Answer 27

because the electron is held close to the oxygen atom than the hydrogens

Question 28

important result of water dipole

Answer 28

water molecules form hydrogen bonds

Question 29

how is a hydrogen bond formed

Answer 29

slightly negative oxygen and slightly positive hydrogen atoms in weak electrostatic called hydrogen bonds

Question 30

list some of waters properties

Answer 30

-polarity transport medium high specific heat capacity cohesive adhesive high surface tension

Question 31

water being polar and its biological importance

Answer 31

-dissolves ionic substances so most chemical reactions occur in water -movement of minerals and blood and waste products in organisms

Question 32

maximum density of water and its importance

Answer 32

as water reached 4 degrees it reached max density -molecules become more wide spaced -ice is less dense and floats forming insulating layer preventing water underneath from freezing -organisms can live underwater when cold

Question 33

waters high specific heat capacity and its importance

Answer 33

-slow to absorb and release heat -lost of energy to break hydrogen bonds -temp of lakes doesnt change so good for organisms -thermostable -high latent heat of vaporisation = cooling without water loss

Question 34

waters compression and its importance

Answer 34

-water is a liquid and cant be compressed -cohesive forces -supporting medium in hydraulic mechanisms

Question 35

waters cohesive and its importance

Answer 35

-forces between molecules mean they stick together -movement of water up plants and streams

Question 36

waters adhesivness and its importance

Answer 36

-attracted to other molecules -important in plant transport and surface tension -mucus lubrication

Question 37

waters high surface tension and its importance

Answer 37

-because of attraction to molecules and hydrogen bonds affects animals living on water