acids and redox

Question 1

sulfuric acid

Answer 1

H2SO4

Question 2

nitric acid

Answer 2

HNO3

Question 3

acid

Answer 3

release H+ in aq sol

Question 4

alkali

Answer 4

release OH- in aq sol

Question 5

strong acid

Answer 5

fully dissociates in sol- rel all of H+

Question 6

weak acid

Answer 6

partially dissociates- rel small prop oh available H atoms as H+

Question 7

what does the ebm sign indicate

Answer 7

the forwards reaction is incomplete

Question 8

example of weak acid

Answer 8

CH3CH2COOH- ethanoic acid

Question 9

neutralisation reaction

Answer 9

reaction of H+ and OH- to form water

Question 10

neutralisation reactions of acids and bases

Answer 10

acid+metal (hydr)oxide-> salt and water

acid+carbonate-> CO2+H2O+salt

Question 11

alkali

Answer 11

water soluble base

Question 12

standard solution

Answer 12

sol of a known conc

Question 13

uses of titrations

Answer 13

finding conc of a sol
identifying unknown chemicals
finding the purity of a substance

Question 14

why is checking impurities important

Answer 14

medicines and food

impurities can cause harm to patients

Question 15

100cm3 volumetric flask

Answer 15

+/- 0.20cm3

Question 16

250cm3 volumetric flask

Answer 16

+/- 0.30cm3

Question 17

preparing standard solution

Answer 17

weigh solid
dissolve w/distilled water
transfer sol to VF, rinse traces 
fill until bottom of meniscus touches graduation line
invert several times

Question 18

effect on titre if volumetric flask filled above graduation line

Answer 18

titre would be less as sol is more dilute

Question 19

how can you accurately fill the flask

Answer 19

view the graduation mark and and meniscus at eye level

Question 20

why is flask inverted

Answer 20

to mix the solution evenly thoroughly

Question 21

effect on titre if flask not inverted

Answer 21

sol used in first titration would be more dilute than sol used later
first titre would need less solution

Question 22

how can you tell the solution mixing as you invert the flask

Answer 22

able to see the more dense original sol move through the sol

Question 23

burette reading

Answer 23

nearest +/- 0.05cm3

2dp

Question 24

how to remove air bubbles from burette

Answer 24

when filling run XS sol through tap

Question 25

acid-base titration procedure

Answer 25

add meas vol of sol in c.flask using pipette
add another sol to burette, record initial
few drops of indicator to c.flask
run sol in burette into sol in c.flask, swirl, end point
record final burette reading
quick trail, repeat until 2 concordant titres

Question 26

swirl c.flsk

Answer 26

to mix the 2 sols

Question 27

indicator

Answer 27

identify when end point is reacted

Question 28

end point

Answer 28

vol of one sol the exactly reacts w/ the vol of 2nd sol

Question 29

titre

Answer 29

vol of sol added from the burette

Question 30

how to calculate the titre

Answer 30

initial- final burette reading

Question 31

trail titration

Answer 31

to find the approximate titre

Question 32

concordant

Answer 32

agreeing w/in 0.10cm3

Question 33

how is titration repeated accurately

Answer 33

adding sol dropwise as endpoint is approached

Question 34

effect on titre if air bubble inside pipette

Answer 34

titre would be less as less sol has been added than the correct pipette volume

Question 35

effect on titre if readings taken from burette at top of the meniscus rather that bottom

Answer 35

no effect as vol is measured by difference bw 2 readings

Question 36

including all titres in the mean

Answer 36

lose accuracy

Question 37

method for analysing results

Answer 37

moles of solute- n=cV
moles of other solute- ratio
unknown info about solute in the other sol