2.9 Gas Chemistry Flashcards
What percent of the atmosphere does nitrogen make up ?
78%
What percentage of the atmosphere does oxygen make up ?
21%
What percentage of the atmosphere does argon make up ?
1%
What percentage of the atmosphere does carbon dioxide make up ?
0.03-0.04%
What percentage do other noble gases make up ?
Small proportions
How much of the atmosphere does water vapor make up ?
Varying proportions
What is meant by soluble gases ?
Gases that are soluble in water
How are gases that are soluble in water collected in the laboratory?
Gases that are soluble in water are collected by displacement of air and so the density of the gas compared to air must be considered
How are soluble gases which are less dense than air collected and give an example of a gas ?
Soluble gases less dense than air must be collected by displacement of air using the upward delivery method e.g. ammonia (NH³) gas
How are soluble gases more dense or denser than air collected ?
Soluble gases that are denser than air must be collected by displacement of air using the downward delivery method e.g. sulfur dioxide (SO2) and hydrogen chloride (HCl) gas
How are insoluble gases collected in the laboratory?
Gases that are insoluble in water are collected over water.
What three insoluble gases are collected over water and why ?
Hydrogen is insoluble in water
Oxygen is only slightly soluble in water
Carbon dioxide slightly solubility in water
Meaning that all three gases are collected over water
What are 3 uses of Hydrogen?
- Hardening oils (to make margarine)
- Clean fuel
- Weather balloons
What are the physical properties of Hydrogen gas ?
-Colourless
- Odourless
- Less dense than air
- Insoluble in water
What is meant by a clean fuel ?
A fuel that doesn’t produce any carbon dioxide pollution
How can Hydrogen gas be used as a clean fuel ?
Because Hydrogen gas burns in oxygen to produce only water which results in its potential use as a clean fuel, the burning of hydrogen produces no carbon dioxide (greenhouse gas) pollution
How can Hydrogen be prepared in the laboratory?
Hydrogen can be prepared in the laboratory by reacting zinc or magnesium metal with an acid. ( Metal + Acid > Salt + Hydrogen)
What is the word equation for the preparation of hydrogen?
Zinc + Hydrochloric acid > Zinc Chloride + Hydrogen
What is the balanced symbol equation for the preparation of Hydrogen?
Zn + 2HC > ZnCl² + H²
What can be observed when preparing Hydrogen in the lab ?
- Bubbles of colourless gas (Hydrogen)
- Grey solid disappears (Zinc)
- Heat is given off ( exothermic reaction)
What is the test for hydrogen ?
- Place a lit splint in hydrogen gas
- Hydrogen burns with a squeaky pop
What are 2 uses of oxygen ?
- Medicine
- Welding
What are the physical properties of Oxygen?
- Colourless
- Odourless
- Less dense than air
- Soluble in water
How can Oxygen be prepared in the lab?
- Oxygen can be prepared from the catalytic decomposition of hydrogen peroxide with the use of a manganese (IV) oxide (MnO²) catalyst.
- Hydrogen Peroxide is a colourless liquid and Manganese (IV) oxide is a black solid.
- A catalyst speeds up a chemical reaction without being used up in the process so the black solid remains
What is the word equation for the preparation of Oxygen?
Hydrogen peroxide > Water + Oxygen
What is the symbol equation for the preparation of Oxygen?
2H²O² > 2H²O + O²
What observations can be seen in the preparation of Oxygen in the laboratory ?
- Bubbles of colourless gas ( Oxygen)
- Heat is given off ( exothermic)
- Black solid remains ( catalyst)
What is the test for oxygen ?
- Place a glowing splint in oxygen gas
- The glowing splint will relight