Perception Of Salts Flashcards
Explain why it is important that magnesium is in excess
To neutrilese all nitric acid so solution only contain magnisium nitrate
Explain titration
1.mesure 25 cm3 of naoH solution with pippette and transfer solution to conical flask
2.add 3 drops of phenolphathline
3.add dilute sulphuric acid in burrette and measure initial volume
3.add the acid drop by drop to the alkali in the flask and swirl until colour change
4.mesure final volume of acid used and repeat to obtain concordant result
Describe how the student can obtain dry crystals of hydrated magnesium nitrate from the mixture at end of reaction (dissolving)
1.add excess solid a little at a time in a beaker half filled with sulphuric acid during stiring
2.filter mixture to remove excess solid
3.heat the filtration and evaporate till Crystillastion pint in evaporating basin
4.leave solution to cool and crystallises when crystals formed on glass Rod
5.seprate by filtration and dry between 2 filter paper
Appaurtas use to add naoh solution
Pippette
Why is is better to use phenolphthalien indicator rather than universal indicator in titration
Has only one colour and give sharp end point
Why we warm acid
To increase Rate of reaction
How will student know when the copper (Ii) oxide is in excess
When solid perciptae formed
How will student know when the crystallisation point reached
When crystals formed on glass rod
Precipitation
1.mix 2 solutions,preciptate of nacl2(ex) formed and stir them with glass Rod
2.filter the mixture
3.wash residue by distilled water to remove any soluble substances
4.dry residue between 2 filter paper r drying oven
Colour of perciptate silver chloride
White
Explain why it is important that magnesium is in excess
To neutrlise all nitric acid so solution only contain magnesium nitrate
State why the student uses an excess of zinc powder
To neutrilise all acid
Give the reason for using the white tile
To see the colour change clearly at the end poiny
Colour change of methyl benzene in acid natural alkali
Red(acid)
Orange(neutral)
Yellow(alkali)
State why we filter mixture in dissolving
To remove excess solid