Gas Chemisty Flashcards
What gases make up air? In what percentage?
Nitrogen 78%
Oxygen 21%
Carbon dioxide 0.03-0.04%
Argon 1%
Water vapour (varying proportions)
What is nitrogen?
Unreactive due to a strong triple covalent bond in the diatomic molecule.
Colourless, odourless gas
Neutral
Insoluble in water
Used as a coolant and in food packaging
What is ammonia?
NH4OH (see notes p3 for diagram)
Colourless gas
Pungent smell
Less dense than air
Very soluble in water
Weak alkali
What are some advantages to nitrogenous fertilisers?
Greater nitrogen uptake by plant - producing larger, healthier plants.
Increase crop yield therefore increases profits.
What are some disadvantages to nitrogenous fertilisers?
If fertiliser gets into rivers it contributes to eutrophication
If it gets into drinking water then can cause stomach cancer and condition in infants known as ‘blue baby’ syndrome.
What is hydrogen?
A diatomic molecule with two atoms bonded by a single covalent bond.
Colourless, odourless gas
Less dense than air
Insoluble in water
Neutral
Used in weather balloons, hardening vegetable oils to make margarine, potential ‘clean’ fuel.
How do you prepare hydrogen for testing?
Measure out 10cm3 of hydrochloric acid and place in test tube.
Add a piece of zinc. Wait 10 seconds and test the gas by holding a lit splint above the level of the liquid in the test tube
Record your observations in the table below.
What are some benefits to using hydrogen as a fuel?
Clean burning fuel - only produces water therefore causes no pollution
Can be used safely in fuel tanks
What are some disadvantages to using hydrogen as fuel?
Must be manufactured.
Difficult to transport and store.
Extremely flammable - leaks are hard to detect.
Hydrogen in fuel tanks must be liquified and stored under high pressure, which is expensive.
Storage tanks must well insulated to maintain these conditions and coated to prevent leaks.
Hydrogen production is highly polluting.
What is oxygen?
Colourless
Odourless
Slightly soluble in water
Neutral
Used in medicine, breathing apparatus, welding, rocket fuel.
How would you prepare oxygen for experimentation?
Measure out 10cm2 of hydrogen peroxide and place in a test tube.
Add half a spatula of manganese(1V) dioxide. Wait 10 seconds and test the gas by holding a glowing splint above the level of the liquid in the test tube
Record observations
What is carbon dioxide?
CO2
Colourless
Odourless
Heavier than air
Slightly soluble in water
Acidic
Used in fire extinguishers, carbonated drinks, dry ice
How would you produce carbon dioxide for experimentation?
Place 3g of calcium carbonate into the conical flask and set up the apparatus as shown in the diagram.
Have three gas jars filled with water and inverted in trough of water.
Slowly pour 50cm3 of hydrochloric acid into the thistle funnel, wait 5 seconds and then carefully place the first water filled gas jar on the beehive over the end of the delivery tube.
Allow gas jar to fill with gas, leave the gas jar in the water to retain the gas and replace it with another water filled gas jar.
Repeat step 4 until three jars of gas have been collected. Remove each gas jar from the water as required for the following tests.
