The Atmosphere And Energy Changes Flashcards
Test for hydrogen
Light wooden splint, should make popping noise in test tube
Test for oxygen
Put glowing splint in test tube with oxygen, should relight
Test for carbon dioxide
Bubble gas through limewater, co2 turns limewater cloudy white.
Test for ammonia
Makes damp red litmus paper blue
Test for chlorine
Makes damp blue litmus paper turn red and then bleaches it white.
What is the composition of clean air
79% nitrogen
20% oxygen
Remainder is a mixture of noble gases, water vapor and carbon dioxide
Common pollutants in the air
Carbon monoxide
Sulfur dioxide
Nitrous oxides
Lead compounds
Which gases contribute to global warming
Carbon dioxide
Methane
Sources of Methane
Decomposition of vegetation
Waste gases from digestion in animals
Difference between exothermic and endothermic réactions
Exothermic reactions transfer energy to surroundings, endothermic reactions take in energy from the surroundings.
For exothermic more stronger bonds are made than broken.
How to calculate heat energy produced per gram of hydrocarbon
q = mc (triangle) T
Combustion of ethanol equation
C2H5OH + 3O2 —> 2CO2 + 3H2O
Exothermic
What is complete combustion
Enough oxygen is present and produce carbon dioxide and water
What is incomplete combustion
Not enough air is present therefore carbon monoxide and water are formed
How to calculate the energy produced per gram
Q = mc x change in temperature/ mass of ethanol burned
Advantages of bioethanol
Exhaust gases are much cleaner
Carbon neutral
Renewable energy source
Disadvantages
Not all motors can use bioethanol
isn’t as energy efficient
Production of ethanol emits greenhouse gases
