Maggie Mitchell
IB Chemistry Prd. 5
The Halogens Lab
Date:
9/11/13
Purpose:
The purpose of this experiment was to observe and record the halogens' (NaF, NaCl, NaBr, and KI) reactions with the chemicals Ca(NO3)2, AgNO3, and NH4OH and use these observations to identify an unknown halogen.
Data:
(see next page)
Table 1: Reactions of Halogens with Ca(NO3)2, AgNO3, and NH4OH | ||||
Reaction | NaF | NaCl | NaBr | KI |
Reaction w/ Ca(NO3)2 | solution turns cloudy and precipitate forms | clear precipitate formed | slightly cloudy precipitate formed | no reaction |
Reaction w/ AgNO3 | no reaction | white, cloudy precipitate formed | thick white/yellow precipitate formed | cloudy yellow precipitate formed |
Reaction w/ NH4OH | does not dissolve; precipitate becomes defined | does not dissolve; precipitate becomes defined | does not dissolve |
Table 2: Reaction of Halogens with Hexane and Chlorine Water | |||
Reaction | NaF | NaBr | KI |
Color of the Top Layer | clear | yellow | pink |
Is this Halogen MORE or LESS active than Cl? | more | less | less |
Table 3: Reaction of Unkown Halogen D with Ca(NO3)2 and AgNO3 | ||
Reaction Used to Test the Unknown | Result of the Test | Possible Identity of the Unknown |
Ca(NO3)2 | solution turns cloudy and precipitate forms | NaF or NaBr |
AgNO3 | no reaction | NaF |
AgNO3/NH4OH | no reaction | NaF |
Questions:
The halogens should have similar chemical properties because they all belong to the same group in the periodic table.
When elements are in the same group that means that they have the same number of valence electrons. Valence electrons determine an element's chemical properties, and when elements have the same amount, it means that they will have similar properties.
When the halogen solutions are mixed with calcium nitrate, generally a cloudy precipitate is formed.
The only halogen to not react this way is KI.
When the halogen solutions are mixed with silver nitrate, generally a thick yellow/white precipitate is formed.