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Unit 2 Chem > REDOX > Flashcards

Flashcards in REDOX Deck (68):
1

Reduction

The gaining of electrons

2

Oxidation

The loss of electrons

3

Oxidant

Gains electrons

4

Reductant

Loses electrons

5

Eg of Reduction (Including Oxidant)

Cu 2+ (aq) + 2e- -> cu (s) Cu 2+ is oxidant

6

Eg of Oxidant (Including Reductant)

Fe (S) -> Fe 2+ (aq) + 3e- Fe is reductant

7

Electrolyte

Solutions that allows ion movments

8

Anode

A Postive Electrode

9

Cathode

A negative Electrode

10

3 types of observations which may be made to indicate that a spontaneous redox reaction has occured

Bubbles at electrode
Colour Change
Deposit of metal on electrode

11

Conjugate redox pairs (ZN as a reductant)

Zn2+

12

Conjugate redox pairs (Fe2+ as a reductant)

Fe3+

13

Would it be sensible to store copper (II) sulfate in an iron tank?

Cu 2+ (aq) + Fe -> Cu (s) + Fe 2+
Cu 2+ is the strongest oxidant and Fe is the strongest reductant. Fe will decompose into Fe 2+ allowing cu2+ to break out. It would not be sensible

14

Conjugate of bases

loses Hydrogen atoms

15

Conjugate of Acids

gains Hydrogen atoms

16

Amphiprotic

Able to act as both an acid and base

17

What is a weak/ Tiprotic acid?

When its weak it means that it does not release H+ readily and Triprotic means that it is ready to donate 3H+ from the substance.

18

State the Bronsted- Lowry definitions of both an acid and base.

Acids donate Protons and base accepts protons

19

What is it meant by a strong acid

Low on the Ph scale and they are more ready to donate protons. They also have high amount of H+ atoms. eg h2so4

20

What is it meant by a strong base

Higher Ph and are more ready to accept protons. and with more OH-. eg is Nacl2

21

Show that H3PO4 is polyprotic

H3Po4+ H2o -> H2Po4 + H3O (INCLUDE STATES)

22

Water has a high surface tension

The water molecules attract one another due to the water's polar property. Insects can walk on the surface of water because of surface tension of water

23

Water has a high heat of vaporisation.

a high input of energy is required to transform one gram of liquid water into water vapor, an energy requirement called the heat of vaporisation

24

Copper (II) Carbonate crystals are added to dilute sulphuric acid

CuCo3 (s) + H2So4 (aq) -> Co2(g) + Cuso4 (aq) + H20 (l)
Co2 bubbles forming would of seen the solution turn blue

25

Show that a reaction between mg and hcl is a redox equation

The Mg reductant is oxidised by H+

26

Q=mc^T
100 g of water at 25.00 degrees absorbs 100J of heat. What is its final temp?

100 divided by (100x 4.18) = 0.24 Degrees
25 degrees plus 0.24 equals 25.2 degrees

27

Q= mc^T
80g of acetone was heated from 25.5 degrees to 63.4 degrees. how much energy was transferred to the acetone during heating?
SHC of acetone = 2.13jg -1

80 x 2.13 x 37.9 = 6458.16 j
= 6.46 KJ of enegry

28

C=

n divided by v

29

Properties of a acid

Tastes sour, Molecular in structure, Forms conducting soloutions

30

What is least likely to act as an acid

A Structure that has non polar bonds

31

When an alkaline solution with a pH of 8 has a large volue of water added to it , the pH will

Fall as the concentration of the OH- ion has decreased

32

Which of the following lists the solutions in order of increasing pH

H2sO4, HNo3, Ch3COOH, H2O, NH3, NaOh

33

The pH of 25.0ml of solution of nitric acid (HNo3) is closest to

[h3o+] = -log(0.002)

34

Hydrolysis

One which a substance reacts with water to form OH- or H3O+ ions.

35

Acid- Base

Protons are being donated to OH- Ions

36

Ionisation

when a substance reacts with to produce.

37

[ OH-]

10^-14 divided by 10^ pH

38

[H30+]

M= 9,2x 10^14
M+ -log(9.2x10^-14 =3

39

Why is Ethanoic acid (CH3C00H) Monoprotic even though it has 4 hydrogen atoms

Because one hydrogen is in a polar bond which can be donated and 3 are not in a polar bond therefor cannot be donated

40

Equation and observation of MgO powder being added to dilute HCL

MgO (s) + 2HCl (aq) -> H2O (l) + Mgcl2 (aq)
The solid powder would disappear

41

the Ph of a 0.010M solution of a strong DIprotic acid will be

between 1.7 and 2.0 as the second proton is only partially donated.
-log(0.01) =2
-log (0.02) = 1.7

42

Neutralisation

The process of an acid reacting with a base. the properties of the acid and base can be cancelled out.

43

Pepitte (Aliquot)

used to transfer fixed volume of solution to conical flask. Rinse with solution that it will transfer

44

Conical Flask

Receives the aliquot. Add 1-2 drops of indicator. Rinse with distilled water

45

Standard Flask

Always used to prepare solution of known concentration.
Rinse with distilled water

46

Burette

Delivers variable volume. Rinse with solution that it will contain

47

Polyprotic Acids

An acid that can donate more than one proton.

48

Self Ionisation of water

Since water can act as both an acid and base, it can also react with itself according to the equation
H2O (l) + H2O (l) -> H3O= + OH-

49

Why is a nuetral solution a pH of 7

Because it has an equal amount of [H+] and [OH-] Ions.

50

Dilution: calc volume of

0.250x 2.15 Divided by 12

51

Standerd Solution

It must have a high state of purity
It must have an accurately known formula
It must be stable

52

Calculate Concentration in gL-1 and mgL-1 for
0.425g Barium Nitrate in 25 ml of solution

25 divided by 1000 = 0.055
0.425 divided by 0.055.
= 480gL-1 and or 4.8x10^-14 mgL-1

53

Corrosion

Oxidation of metals by materials in their enviroment

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Dry Corrosion

When a metal reacts differently with oxygen. K and Na combine readily with oxygen so they undergo dry corrosion quickly

55

Wet Corrosion rusting

When a metal reacts with oxygen in the presence of water. Water can speed up corrosion reactions.
Fe (s) -> Fe 2+ (aq) +2e-

56

Adverse effects of corrosion

A severly corroded metal cannot conduct electricity.
Products of corrosion are brittle and flake off.
Metal oxides have less tensile strength.

57

Corrosion Protection

Surface Protection
Alloying
Electrochemical Protection

58

Surface Protection + equation

A metal surface being prevented from being into contact with oxygen, such as using oil.

59

Alloying + equation

Iron can be alloyed with small quantities of metals such as chronium, nickel, manganse to produce stainless steel

60

Electrochemical Protection + equation

placing a more reactive metal in a electrical contact with the metal that needs protection

61

Zinc and Copper2+ Displacement reaction

When zinc was placed in copper sulfate solution a reaction occurs, causing copper metal to form Zinc.
Zn (s) + Cu2+ (aq) -> Zn2+ (aq) + Cu (s)

62

Concentration dosent determine strength. it is based on

the amount of ions and how much acid in the solution

63

Chemical equation of ethonaic acid reacting h20

Ch3CooH+ H20 -> Ch3COO- + H30+

64

Nuetralisation equation

HCL (aq) + NaOH (aq) -> NaCl (aq) + h20

65

Ionic equation of nuetralisation

H3O + (aq) + OH- (aq) - 2H20 (l)

66

Corrosion of Iron

2Fe(s) + O2 (g) +2h2o (l) -> 2Fe(OH)2 (s)

67

Copper and Zinc 2+ reaction

No reaction would occur. this makes zinc more reactive

68

Calculate pH of solution Ca(OH)2

10^-14 divided 0.02 then -log( )