group 7, halogens

Question 1

flourine gas colour?

Answer 1

pale yellow gas

Question 2

chlorine gas colour

Answer 2

pale green gas

Question 3

bromine colour

Answer 3

brown-orange liquid

Question 4

iodine colour

Answer 4

grey solid

Question 5

explain the trend of boiling point going down group 7

Answer 5

the boiling point increases going down the group. This is because VDW forces increase due to the increasing size and relative mass of the atoms. as you go down the group the physical state goes from gas at the top of group 7 to solid at the bottom

Question 6

explain the trend of electronegativity going down group 7?

Answer 6

decreases as we go down the group. electro negavity is the abiltiy of an atom to attract a shared pair of electrons (towards itself) in a covalent bond. The atom gets larger and the distance between the postiive nucleus and bonding electrons increases. hence there is more shielding.

Question 7

reativity trend down group 7?

Answer 7

decreases.

Question 8

for a reaction to occur, what must happen?

Answer 8

an electron is gained

Question 9

atoms with a smaller radius, do what better than larger atoms?

Answer 9

attract electrons better than larger atoms.

Question 10

more reactive halogens will _____ less reactive halide ions

Answer 10

displace

Question 11

in terms of being oxiding. what trend is that going down g7

Answer 11

halogens are less oxidising going down the group

Question 12

A HALOGEN WILL DIPLACE A HALIDE FROM SOLUTION IF WHAT?

Answer 12

THE HALIDE IS LOWER IN THE PERIODIC TABLE.

Question 13

show some reaction of halogens with halide ions?

Answer 13

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Question 14

what reaction is bleach made in?

Answer 14

via a disproportionation reaction

Question 15

bleach consists of ….

Answer 15

mixing chlorine with sodium hydroxide to form sodium chlorate (I) solution.known as bleach

Question 16

in the reaction to form bleach, why is it named a disproportionation reaction. (give the reaction)

Answer 16

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Question 17

uses of sodium chlorate (I) i.e bleach?

Answer 17

treating water
bleaching papers and fabrics (making them witer)
cleaning agents (bleach)

Question 18

adding chlorine to water can ___ bacteria in water

Answer 18

kill

Question 19

adding water to chlorine will produce what type of ions which can do what.

Answer 19

adding water to chlorine will produce chlorate (I) ions (CLO-) which kill bacteria. useful in drinking water and pools

Question 20

show the disproptionation reaction of h20 + cl2 and state why its a disproportionation reaction

Answer 20

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Question 21

give the reaction for when water reaction with cl2 in the presence of sunlight can state what this sunlight does and what that leads to in terms of killing the bactiera in water?

Answer 21

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Question 22

ADVS and disadvs OF CHLORINATING DRINKING WATER?

Answer 22

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Question 23

HALIDE IONS LOSE AN ELECTRON IN REACTIONS, so they are what type fo agents?

Answer 23

reducing agents

Question 24

GIVE THE TRENT OF THE REDUCING POWER OF HALIDE IONS GOING DOWN THE GROUP, and give the name of the 2 tests to prove this trend?

Answer 24

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Question 25

How do halide ions react with concentrated sulfuric acid, and how do the reactions vary between Cl⁻, Br⁻, and I⁻?

Answer 25

https://merchanttaylorsschools-my.sharepoint.com/:w:/g/personal/tofoma_merchanttaylors_com/EZb70YdFkvREhRic_LEEbuUBHX07RSmOQaHL3N8t6BldTQ?e=tBGZqF IMPORTANT TO NOTE THAT DEPENDING ON THE HALIDE ION, H2SO4 GETS REDUCED TO SO2, S AND H2S. FOR EG WITH BR2 IT GETS REDUCED TO SO2. WITH I2 IT GETS REDUCED TO S, AND FURTHER GETS REDUCED TO H2S. THESE ARE ALL THE REDUCTION PRODUCTS SHOWING THE REDUCING POWER OF THE HALIDE ION, IODINE BEING THE STRONGEST. (with chlorine nacl+h2so4 gives nahso4 + hcl thats it)

Question 26

How do you test for halide ions using silver nitrate, what colours indicate each halide, why is nitric acid used, and how does ammonia help confirm the result?

Answer 26

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Question 27

what are the colours given in the flame test involving ca2+, Sr2+ and Ba2+.

Answer 27

ca2+ - dark red Sr2+ - Red Ba2+ - green

Question 28

how do u test for ammonium compounds, and given the overall reaction.

Answer 28

add sodium hydroxide (NaOH), gently heat and if ammonium compound is present, ammonia gas will be produced. to test for that ammonia use damp red litmus paper. ammonia will dissolve in the water and turn litmus paper blue if its present. NH4+ (aq) + OH- (aq) ------> NH3 (g) + H2o(l)

Question 29

how do u test for hydroxide ions?

Answer 29

hydroxides are alkaline and they will turn red litmus blue. this test doesnt mean u will definitely have hydroxides. red litmus turns blue for any alkali. further tests are needed to confirm u have a hydroxide

Question 30

how do u test for carbonates?

Answer 30

ADD HCL, if carbonates present CO2 is produced. Co2 is then bubbled through limewater, and limewater turns cloudy.

Question 31

testing for sulfates and give the ionic equation

Answer 31

add hcl to remove any carbonates in. (the reason is is that these could ppt out after addium barium chrloride giving a flase result). ADD BARIUM CHORIDE white ppt of barium sulfate forms if sulfate is present. - this is insoluble Ba2+(Aq) + so4 2- (AQ) -----> BAso4 (s)