Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

OCR A-level Chemistry Module 3: P.T. and Energy > Reactivity Trends > Flashcards

Reactivity Trends Flashcards

the part of module 3 that ties loose ends and knowledge...!

1
Q

How does Atomic Radius, 1st IOnisation energy and Melting Points change down Group 2?

A
  1. More Shells = Larger atoms!
  2. Larger atoms = more shells = more sheilding = lower I.E!
  3. Weaker metallic bonding = lower melting points!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does reactivity change down Group 2?

:

A
  • Will increase, as ionisation energy decreases
  • Easier to loose outermost electrons as atomes increase in size!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does alkilinity change down Group 2?

A
  • Down the group, solubility of hydroxides will increase
  • pH will increase, as concentration of OH- ions released will increase
  • Hence, increase in alkalinity!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Use of Group 2 compounds?

A
  1. Ca(OH)2 = Soil Neutralisation
  2. Mg/Ca (OH)2 = Stomach Indigestion Tablets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Physical Properties of Halogens?

A
  1. Flourine = Yellow Gas, Toxic+Reactive
  2. Chlorine = Green Gas, Toxic+Reactive
  3. Bromine = Brown Liquid+Orange Vapour
  4. Iodine = Grey Crystal Solid+ Purple Vapour Gas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Halogen colours in Water and Organic Solvent?

A
  1. Chlorine = Pale Green (both)
  2. Bromine = Orange (both)
  3. Iodine = Brown in water, Violet in O.S.!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does Boiling Points change down Group 7?

A
  1. Boiling Points increase!
  2. Due to more electrons per atom = Greater London Forces in induced d-d interactions
  3. more energy required to break the London Forces!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does solution colour indicate about reaction in Halide Displacements?

A
  • Colour = Element being displaced in reaction, from its compound!
  • HENCE, NO LONGER IN ION FORM!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does Reactivity change going down Group 7?

A
  • Reactivity AND OXIDISING POWER will decrease!
  • increasing atomic radius and increasing shielding
  • This will mean more repulsion and less NUCLEAR electrostatic attraction with outermost electrons and positive nucleus
  • Less able to attract 1 electron to complete outer shell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are 2 main examples of Disproportionation in halogens?

A
  1. Cl2 + H2O&raquo_space; HClO + HCL!!
  2. Cl2 + NaOH&raquo_space; NaClO + NaCl + H2O!!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the main uses of the main 2 Disproportiation reactions for Halogen?

A
  • Producing both Chloric Acid and Hydrochloric Acid will act as water purification
  • Bacteria are killed by ClO- ions and HCL, while ClO- ion acts as weak bleach, being alkaline!
    1. Producing Sodium Chlorate will provide a very large concentration of chlorate ions, providing ions for home bleach!
    2. Reaction MUST BE COLD with DILUTE NaOH, otherwise NaClO3 is produced, instead of NaClO
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Risks vs Benefits of using Cl2 for water purification?

A
  1. Good = Kills bacteria, Disinfects water
  2. Bad = Toxic, can react with organinc hydrocarbonds present ( Chlorinated hydrocarbons&raquo_space; cancer……)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How can we combine Silver Nitrate test for halogens, with aqueous Ammonia?

A
  1. Ag+ ion gives WHITE = Cl, CREAM = Br, YELLOW = I2
  2. however! we can use aqueaous ammoniato give CLARITY and GREATER CONTRAST for halogens: Chloride = soluable at low conc Bromide = Soluable at high conc only Iodide = Completely Insoluable!

[Ag+ + X-&raquo_space; AgX(s)]

PRECIPITATES REMAIN THE SAME INITIAL COLOUR WITH Ag+ WITH ALL AMMONIA TESTS!!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Testing for Carbonate Ions!

A
  1. React with any acid, will produce CO2
  2. Bubble gas through limewater = Cloudy solution (solid precipitate!)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Testing for Sulfate Ions!

A
  1. Add testing compound to soluable Barium Salt, = Barium Sulfate + Soluable Salt
  2. Solid, White precipitate will form!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Testing for Halide Ions!

A
  1. Add silver nitrate to aqueous halide solution
  2. Silver halide will form in reaction, being insoluble (Cl=White,Br=Cream,Iodine=Yellow)
  3. AND, AQUEOUS AMMONIA used to FURTHER DIFFERENTIATE the halide solutions via solubliities! (Cl=dilute,Br=conc,Iodine=not even conc…)
17
Q

Testing for Ammonium Ions!

A
  1. Add sodium hydroxide to solution, and gently warm (no bubbles as ammonia gas is VERY soluble in water….)
  2. DAMP LITMUS PAPER turns BLUE!
18
Q

Name the order of ion testing and EXPLAIN!!

A
  1. Carbonate = FIRST, only carbonate ions can produce evervesence with diluted acid
  2. Sulfate = SECOND, carbonate ions can STILL form precipitates with barium (BaCO3), so only continue when there no carbonate
  3. Halide = THIRD, carbonates and sulfates form precipitates with silver nitrate, means false positives must be avoided
19
Q

When MULTIPLE ION TESTING, what should be done….?

A
  1. Add excess acidic substance, ensuring ALL RECTANT TESTS has been USED
  2. Prevents no more leftover reactant carried over to following tests (false positives)…
  3. Add EXCESS BARIUM NITRATE until no more precipitate formed!! + Filter precipitate FULLY fom solution!
20
Q

What is Oxidising Power?

A
  1. Refers to the ability of a substance to accept electrons during a chemical reaction.
  2. In simpler terms, it’s the capacity of an oxidising agent to oxidize another substance

OCR A-level Chemistry Module 3: P.T. and Energy (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions