Chemistry ATP (Important points for Both IGCSE and O-level)

[WayneRooney10]

hey!! Can any one give me a list of all the indicators and how they work? Thanks.

 

[TatsuEG]

Hey guys, Assalam-o-Alaikum
These are some of the tips for Chemistry ATP (both O-level and IGCSE)

Some precautions:
=> Experiments involving poisonous gases like Nitrogen, Ammonia and Bromine -> Carry out the exp. in Fume Cupboard or in a well Ventilated Room.
Umm, Nibz, nitrogen is not toxic/poisonous. Otherwise, we'll all be dead breathing 78% of nitrogen in air 24/7!

Oxygen is a poisonous gas , if we inhale it directly from an Oxygen source

We don't die from oxygen in air , because other gases are in the atmosphere with it


So I think nitrogen might be a poisonous gas if inhaled directly from the source
Its just an opinion
Thanks

 

[Nibz]

Umm, Nibz, nitrogen is not toxic/poisonous. Otherwise, we'll all be dead breathing 78% of nitrogen in air 24/7!

My Bad!
Sorry.
That was supposed to be 'Nitrogen Dioxide'!

 

[abcde]

Okay!

 

[burndtjamb]

For which substances can potassium dichromate be used as a test for?

 

[TatsuEG]

hey!! Can any one give me a list of all the indicators and how they work? Thanks.

Universal Indicator:

Acid ( Red - Yellow) , Neutral ( Green) , Alkaline ( Blue - Violet)


Phenolphthalein:

Alkaline ( Pink) For Strong ( Colourless) , Neutral ( Colourless) , Acid ( Orange)

Methyl Orange:

Alkaline: ( Yellow) , Neutral ( Colourless) , Acid ( Red)


P.S Some of the indicators have a trend in colour , such as methyl orange from 1-14 colour becomes more pale

Hope that helped,
Thanks

 

[TatsuEG]

For which substances can potassium dichromate be used as a test for?

Testing for Ethanol

Thanks

 

[abcde]

For which substances can potassium dichromate be used as a test for?

To test for the presence of any reducing agent.

 

[dancingmaster]

hey!! Can any one give me a list of all the indicators and how they work? Thanks.

Universal Indicator:

Acid ( Red - Yellow) , Neutral ( Green) , Alkaline ( Blue - Violet)


Phenolphthalein:

Alkaline ( Pink) For Strong ( Colourless) , Neutral ( Colourless) , Acid ( Orange)

Methyl Orange:

Alkaline: ( Yellow) , Neutral ( Colourless) , Acid ( Red)


P.S Some of the indicators have a trend in colour , such as methyl orange from 1-14 colour becomes more pale

Hope that helped,
Thanks

Doesn't phenolphthalein only change colour in alkalis? Isn't it supposed to be colourless in acids? and what about the bromo-something blue? what colour changes does that have? PLEASE HELP!

 

[TatsuEG]

hey!! Can any one give me a list of all the indicators and how they work? Thanks.

Universal Indicator:

Acid ( Red - Yellow) , Neutral ( Green) , Alkaline ( Blue - Violet)


Phenolphthalein:

Alkaline ( Pink) For Strong ( Colourless) , Neutral ( Colourless) , Acid ( Orange)

Methyl Orange:

Alkaline: ( Yellow) , Neutral ( Colourless) , Acid ( Red)


P.S Some of the indicators have a trend in colour , such as methyl orange from 1-14 colour becomes more pale

Hope that helped,
Thanks

Doesn't phenolphthalein only change colour in alkalis? Isn't it supposed to be colourless in acids? and what about the bromo-something blue? what colour changes does that have? PLEASE HELP!

It gives colourless on weak acids


Bromothymol Blue:

Acid (Yellow) , Neutral (Dark green) , Alkaline (Blue)

 

[WayneRooney10]

hey!! Can any one give me a list of all the indicators and how they work? Thanks.

Universal Indicator:

Acid ( Red - Yellow) , Neutral ( Green) , Alkaline ( Blue - Violet)


Phenolphthalein:

Alkaline ( Pink) For Strong ( Colourless) , Neutral ( Colourless) , Acid ( Orange)

Methyl Orange:

Alkaline: ( Yellow) , Neutral ( Colourless) , Acid ( Red)


P.S Some of the indicators have a trend in colour , such as methyl orange from 1-14 colour becomes more pale

Hope that helped,
Thanks

Thanks Alot

 

[babyzee]

http://www.xtremepapers.me/CIE/Cambridg ... 9_qp_6.pdf can any help me with q5.. this questions come up a lot..and technique of doing these types. PLEASE HELP

 

[babyzee]

http://www.xtremepapers.me/CIE/Cambridg ... 9_qp_6.pdf can any help me with q5.. this questions come up a lot..and technique of doing these types. PLEASE HELP

 

[TatsuEG]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0620%20-%20Chemistry/0620_w09_qp_6.pdf can any help me with q5.. this questions come up a lot..and technique of doing these types. PLEASE HELP

Here are some Ion testing so you could solve the questions

http://www.xtremepapers.me/forums/viewtopic.php?f=24&t=667

All rights reserved to the owner


Hope it helps

 

[babyzee]

Tatueg can you take me through one question like exactly how to do it

 

[TatsuEG]

Tatueg can you take me through one question like exactly how to do it

Very well...

You have been given 3 Aqueous Solutions. K , L , M

L was identified as sodium hydroxide

The first question on the table says

"Ph of L" L is sodium hydroxide which is an alkali

Alkalis have a range of Ph from 8-14 . Sodium hydroxide is a strong alkali so you should provide any ph from the range of 11-14

2nd Question in the table says
What happens if we drop Sodium hydroxide on Copper sulphate

When Sodium hydroxide is added to Copper ion , a Blue precipitate is formed and does not dissolve in Excess of Sodium Hydroxide

Only when Excess ammonia is added , It dissolves giving a Pale blue solution as mentioned in the table


3rd Question in the table says
If Sodium Hydroxide was added to Aluminium Sulphate
Results would be

White precipitate , If in excess would dissolve giving a colourless solution

K is identified as Aqueous Ammonia

and M is identified as Hydrochloric acid duo to acidification and adding silver nitrate and forming a white ppt. which is a typical for a chloride ion test , Donot provide only chloride ion for 2 marks provide a chloride compound such as Hydrochloric acid.

 

[dancingmaster]

Doesn't phenolphthalein only change colour in alkalis? Isn't it supposed to be colourless in acids? and what about the bromo-something blue? what colour changes does that have? PLEASE HELP![/quote]

It gives colourless on weak acids


Bromothymol Blue:

Acid (Yellow) , Neutral (Dark green) , Alkaline (Blue)[/quote]

Thanks a lot. Just one more question - Does phenolphthalein change colours in strong acids and if it does, what colour change happens?

Again thank you so very much.

 

[TatsuEG]

Orange colour

 

[Nibz]

Waalaikumassalam!!

wud like to gie a sugestion...post it as a word doc. as well..with all formatting i mean...it's more easier and better wen u see i wit different kin of colours and formatting and all tat

Anyways thanks a lot! Jazak ALlah Khair!! gud work!

If only I had time!
You can do that, if possible !

 

[Ramosk95]

how would i know when to use the right test for water for example :give a test for pure water in the ms they said boiling then the result is 100 but i wrote copper 2 sulphate and its result!! is that correct???thanks