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                        Lab 1 : Alkali Metals

Purpose: to describe the chemical properties of two elements in the alkali metal family

Experiment Procedure:

1.  Obtain a 250 mL beaker, fill it about 100 mL with water.

2.  Obtain a piece of Sodium (Na) from the teacher in a Petri dish.

            CAUTION!  DO NOT TOUCH IT !  WEAR GOGGLES!

3.  Describe the piece of sodium. Touch it with the forceps. 

            How hard is it?  Can it be poked with the forceps?

            Does it smell?

Solid, Grey dull, like clay can be cut with knife, shiny in the inside

4.  Add the small piece of solid Na to the beaker of water.

            a.   Observe its reaction with water carefully.  You are only going to do this once.

fizzes and creates a bubble of gas on the surface, some smoke, some yellow spark or flame, popping crackling sound

            b.   The teacher will collect the gas product and test it.   Describe the test.

a lit splint caused the gas in the tube to ignite with a yellow/orange flame, some “popping/ whooshing noise”

5.  Obtain a dropper bottle or beaker and dropper filled with Phenolphthalein.Indicator.(PhTh)  What colour is it?

     Now add 2-3 drops of the PhTh to the beaker where Sodium reacted with the water Observe.

the clear PhTh turns a pink/purple  (fucia, magenta…)

Teacher Demonstration:                                                                                 

6.    Describe the reaction of Potassium (K) as shown by the teacher.

the postasium is dull grey on the outside and shiny bluish/purple on the inside,

it reacted violently with the water, producing a violet flame interspersed with yellow sparks,

the water at the end turned the PhTh pinkish.

Questions and Conclusions

:

1.  What makes sodium a metal?

both were shiny, probably conduct electricity, and can be bent (ductile)

2.  The test for a chemical containing Hydroxide (OH) is that phenolphthalein turns pink.

Use the results of your test in procedure step (5) to help you determine the unknown      products in the equation below.

* (Balance the equation and include subscripts (s),(l),(g) or (aq)

2Na _(s)  +  H₂O_(l) à   2NaOH _(aq) + H_2(g)

3.  From your observations of the teacher demonstration, why can you conclude that Na and K are in the same family of chemical elements on the Periodic Table?

both Na and K react similarly  and have similar properties