Required Practicals - Identifying ions Flashcards
What is the goal of the identifying ions practical?
Using chemical tests to identify the ions in unknown single ionic compounds.
What is the apparatus of the identifying ions practical?
-Bunsen burner
-Test tubes and test tube rack
-Teat pipette
-Nichrome wire mounted in handle or cork
-limewater
-0.4 mol/dm3 dilute hydrochloric acid
-0.1 mol/dm3 barium chloride solution
-0.4 mol/dm3 dilute nitric acid
-0.05 mol/dm3 silver nitrate solution
What is the method for the Flame Tests?
-Pour about 1cm depth of each of the labelled chloride solutions into 5 test tubes in the rack.
-Dip the nichrome wire into the first solution. Then hold the tip of the wire in a blue Bunsen burner flame.
-Record your observations in a table.
-Clean the wire carefully.
-Repeat this for the other solutions
-Empty and clean the test tubes.
What flame colour does Lithium and Calcium produce?
Crimson - Lithium and orange/red - Calcium
What flame colour do Sodium, Calcium and Copper produce?
yellow - Sodium, lilac - Potassium, green - Copper
What is the method for the Carbonate test?
-Pour about 1cm depth of each of the labelled sodium solutions into five test tubes in the rack.
-Place 1cm depth of limewater in a sixth test tube.
-1cm depth of dilute hydrochloric acid to each sodium salt solution.
–If you see bubbles, use the teat pipette to transfer the gas produced to the limewater.
-Record results in a table.
What change occurs when carbonate is present in the carbonate test?
Effervescense occurs and the solution goes cloudy.
What change occurs when Sulfate, Chloride, Bromide or Iodide are present in the carbonate test?
No change.
What is the method for the sulfate test?
-Pour about 1 cm depth of each labelled sodium solution into 5 test tubes in the rack.
-Add a few drops of dilute hydrochloric acid to each solution. Then add 1cm depth of barium chloride solution.
-Record the observations and empty and clean the test tubes.
What change occurs when sulfate is present in the sulfate test?
It forms a white precipitate.
What change occurs when Carbonate, Chloride, Bromide or Iodide are present in the sulfate test?
No change.
What is the method the Halide test?
-Pour about 1cm depth of each of the labelled sodium solutions into 5 test tubes on the rack.
-Add a few drops of dilute nitric acid to each solution. Then add 1cm depth of sliver nitrate solution.
-Record the observations.
What change occurs when chloride is present in the halide test?
A white precipitate forms.
What change occurs when Bromide is present in the halide test?
A cream precipitate forms.
What change occurs when Iodide is present in the halide test?
A yellow precipitate forms.
