Chemical tests Flashcards
What is the test for Hydrogen gas?
Lit splint, and a squeaky pop.
How do you test for Oxygen gas?
A glowing splint that relights
What is the test for Chlorine gas?
Litmus paper - Damp litmus paper bleaches (turns white).
What is the test for Ammonia gas?
Litmus paper - Turns damp red litmus paper blue.
What is the test for Carbon Dioxide gas?
Limewater - goes from colourless to milky/white
Describe the procedure for a flame test
- Use a clean Nichrome wire
- heat it
- dip in HCL
- collect a small sample of the compound and observe the flame’s color.
What flame color indicates the presence of Lithium ions (Li+)?
Red Flame
What flame color indicates the presence of Sodium ions (Na+)?
Yellow Flame
Which cation produces a lilac flame in a flame test?
Potassium ions (K+).
What flame color indicates the presence of Copper(II) ions (Cu2+)?
Blue-green flame.
How do you test for Ammonium ions (NH4+)?
Using sodium hydroxide solution and heating it
What is the result of a hydroxide test for Copper(II) ions (Cu2+)?
Light blue precipitate formed.
What is the color of the precipitate formed in the hydroxide test for Iron(III) ions (Fe3+)?
Red-brown precipitate
How do you test for Carbonate ions (CO3 2-)?
Add dilute acid, observe effervescence, and test the released gas, which turns limewater milky.
What is the result of a chloride ion test using acidified silver nitrate solution?
White precipitate formed
How do you test for Sulfate ions (SO4 2-)?
Acidify with dilute nitric acid and add aqueous barium nitrate, resulting in a white precipitate.
How can you physically test whether a sample of water is pure?
Check its boiling point; pure water should have a boiling point of exactly 100 degrees Celsius.
Describe the test for the presence of water using anhydrous copper(II) sulfate.
Anhydrous copper(II) sulfate is white; when water is present, it turns blue.
What effect do impurities generally have on the boiling point of a substance?
Impurities tend to raise the boiling point.
What is the color of the flame in a flame test for Potassium ions (K+)?
Lilac
What is the result for the presence of Bromide ions (Br-) using acidified silver nitrate solution?
Cream precipitate formed.
Describe a chemical test to show that a substance contains ammonium ions
- add sodium hydroxide solution and warm
- Test ammonia with damp red litmus paper
- Turns blue
Describe a chemical test to show that a substance contains chloride ions
- Add silver nitrate
- Add dilute nitric acid
- White precipitate forms
Suggest what property of hydrogen makes it suitable for filling balloons
LOW DENSITY
