Chemistry Halogens Lab

Essay by mem227High School, 11th gradeA-, February 2014

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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.