C4.2.1 - Detecting Gases Flashcards
What do you use to detect carbon dioxide?
Limewater
What is limewater?
A calcium hydroxide solution
What happens to limewater when carbon dioxide is bubbles through it?
It turns cloudy white
What is formed when calcium hydroxide reacts with carbon dioxide?
Water
White precipitate of calcium carbonate
Why does limewater turn cloudy white when carbon dioxide is bubbled through it?
The reaction between calcium hydroxide and carbon dioxide creates a white precipitate which changes the colour
What forms when chlorine dissolves in water?
An acidic solution
Describe the chlorine test.
Dampen a piece of blue litmus paper. Hold the litmus paper above the solution. If the litmus paper turns red then white, then chlorine is present
How do you test for hydrogen?
Hold a lit splint by the gas. If the splint extinguishes with a squeaky pop, then hydrogen gas is present
How do you test for oxygen?
Hold a glowing splint near the gas. If the splint reignites, then oxygen is present
Why must you be careful when inhaling substances?
They can be harmful or toxic
Describe how you should smell a substance?
Hold the solution away from your nose. Fill most of your lungs, and slowly waft the smell towards you. Take a cautious sniff, so you do not inhale too much
