4.6 Chemical Analysis Flashcards
(20 cards)
What ion turns a flame red?
Lithium (Li)
What ion turns a flame yellow?
Sodium (Na)
What metal ion turns a flame lilac?
Potassium (K)
What metal ion turns a flame orange-red?
Calcium (Ca2+)
What metal ion turns a flame blue-green?
Copper (Cu2+)
Why is the wire loop made of platinum?
Due to high melting points
Why is the wire loop dipped in hydrochloric acid first?
So it is cleaned so nothing will contaminate the test
What acid is added to test for metal ions?
Sodium Hydroxide
What metal ion turns a precipitate green? (Positive test w NaOH)
Iron (II) (Fe2+)
What metal ion turns a precipitate brown? (Positive test w NaOH)
Iron (III) (Fe3+)
What metal ion turns a precipitate blue? (Positive test w NaOH)
Copper (Cu2+)
What 2 metal ions turns a precipitate white? (Positive test w NaOH)
Calcium (Ca2+) and Aluminium (Al3+)
How can you test for ammonium?
Using damp red litmus paper in NaOH it turns blue
How do you test for carbonates?
Add dilute HCl, if effervescence occurs bubble through limewater and if it goes cloudy a carbonate is present
How do you test for sulphates?
Add barium chloride and a white precipitate forms
How do you carry out the tests for Halide ions: Cl, Br, I?
Add dilute nitric acid and then silver nitrate.
How would you know if Chloride has formed in the halide test?
Milky white precipitate forms
How would you know if bromide has formed in the halide test?
Cream precipitate would form
How would you know if Iodide has formed in the halide test?
Yellow precipitate forms
How can you test for chlorine gas?
Use damp blue litmus paper which will bleach
