Ch 25 Air and Oxygen Flashcards
How to test for carbon dioxide?
Limewater turns milky
What is used to show water vapours present in air
Anhydrous copper sulphate (white➡️blue) or cobalt chloride paper (blue➡️pink)
What is hydrogen peroxide used for air?
A colourless liquid that slowly decomposes to give off oxygen and form water
___ ➡️ water + oxygen
Hydrogen peroxide
Preparation of oxygen using hydrogen peroxide chemical equation explain:
2 amount of hydrogen peroxide ↪️ 2 amounts of water + 1 amount of oxygen
What compound is used to make hydrogen peroxide decompose quicker
Manganese dioxide (catalyst)
Catalyst?
A substance that changes the speed of a reaction but is not used up in the reaction itself.
What proves that oxygen is a neutral gas?
Place some red/blue litmus papers in a jar of gas ↪️ no change in colour
What proves that oxygen rekindles a glowing splint
Light a wooden splint. Place in jar ( burns vigoriously) Take out and shake it to make it just glow Place in jar Glowing splint is rekindled
How is carbon dioxide formed using oxygen
Heat a small amount of carbon (charcoal) on a deflagrating spoon.
Place glowing carbon in jar
Carbon+oxygen= carbon dioxide
Carbon dioxide and water:
Place a burning carbon in gas jar
Add water + blue litmus paper
Shake jar
Blue↪️ red = carbonic acid
Magnesium and oxygen
Burn magnesium metal in air(bright)
Burn magnesium in gas jar ( more vigoriously + bright white flame)
= white powder Magnesium oxide
Magnesium hydroxide?
Magnesium oxide + water
After making magnesium oxide add moist res litmus paper to the cooled down gas jar. Red- blue (base)
3 chemical properties of oxygen:
- combustion
- reacts with most elements to form oxides
- no effect on litmus
3 physical properties of oxygen:
- colourless,odourless,tasteless
- soluble in water
- heavier than air
