Test 5: Biogeochemical Cycles, Balancing and Stoichiometry Flashcards
What are the reactions of the carbon cycle?
- Photosynthesis
- Respiration
- Combustion
What reduces the amount of carbon in the atmosphere?
- Dissolution of carbon in water
- Photosynthesis
What adds to the amount of carbon in the atmosphere?
- Combustion
- Respiration
- Volcanic eruptions
- Forest fires
- Decomposition
What is the greenhouse effect?
1) Heat from sun warms the Earth
2) Earth radiates heat
3) Greenhouse gases reflect heat back (keep Earth warm)
What’s the positive to the greenhouse effect?
The temperature would be -28 degrees without it (it keeps the Earth warm).
What’s the negative to the greenhouse effect?
If there’s too much it will contribute to climate change/global warming.
What’s nitrogen fixation?
When bacteria convert N2 to NO2 or NO3.
What’s ammonification?
When bacteria converts NO2 or NO3 to NH3 or NH4.
What is nitrification?
When bacteria converts NH3 or NH4 to NO2 or NO3.
What is denitrification?
When bacteria converts NO2 or NO3 to N2.
What is the order of the steps in the nitrogen cycle?
1) Nitrogen fixation
2) Ammonification
3) Nitrification
4) Denitrification
What is the phosphorous cycle?
- Phosphorous moves into water through erosion.
- Phosphorous is absorbed into animals.
- Through decomposition - organic (dead fish) to inorganic (phosphorous).
- Due to decomposition - phosphorous can promote algae growth.
What is eutrophication?
It is the enrichment of a waterbody with nutrients (nitrogen, phosphorous), resulting in the excessive growth of photosynthetic organisms (algae) and depletion of dissolved oxygen via decomposition (decomposers need lots of O2).
What are the steps of eutrophication?
1) Algae gets fed and grows.
2) Algae bloom blocks light - takes nutrients.
3) Plants/others due and sink.
4) Less oxygen in water, more organisms (fish) die.
What is a better alternative to fertilizer used to replace nutrients in agriculture?
Compost - no excess nutrients.
What are the 5 chemical reactions?
- Photosynthesis
- Respiration
- Combustion
- Oxidation
- Neutralization
What’s photosynthesis?
6 CO2 + 6 H2O + Energy —-> C6H12O6 + 6 O2
What’s respiration?
C6H12O6 + 6 O2 —-> 6 CO2 + 6 H2O + Energy
What is combustion?
Element + Oxygen —-> Carbon Dioxide + Water
What are the sources of combustion?
- Volcanic eruptions
- Forest fires
- Fossil fuels
What’s oxidation?
Oxygen is a reactant.
What’s neutralization?
Acid + Base —-> Salt + Water
What is the law of conservation of mass?
What goes in, must come out.
Balance: 2 Fe2O3 + 3C —-> 3 CO2 + 2 Fe
2 Fe2O3 + 3C —-> 3 CO2 + 4 Fe
Balance: AlBr3 + K2SO4 —-> KBr + Al2(SO4)3
2 AlBr3 + 3 K2SO4 —-> 6 KBr + Al2(SO4)3
Balance: CF4 + Br2 —-> CBr4 + F2
CF4 + 2 Br2 —-> CBr4 + 2 F2
Balance: Na3PO4 + CaCl2 —-> NaCl + Ca3(PO4)2
2 Na3PO4 + 3 CaCl2 —-> 6 NaCl + Ca3(PO4)2
Blance: Al + HCl —-> H2 + AlCl3
2 Al + 6 HCl —-> 3 H2 + 2 AlCl3
What does stoichiometry do?
It calculates how much of each chemical we need to produce while respecting the law of conservation of matter.
2 KClO3 —-> 2 KCl + 3 O2
How many moles of O2 can be produced by letting 12.00 moles of KClO3 react?
2 mol KClO3/12 mol KClO3 = 3 mol O2/x
x = 18 mol O2
2 K + Cl2 —-> 2 KCl
How many grams of KCl is produced from 2.50 grams of K and excess Cl2?
78.20g K/2.50g K = 149.10g KCl/x
x = 4.77g KCl
C3H8 + 5 O2 —-> 3 CO2 + 4 H2O
How many moles of CO2 will be produced from 25g C3H8?
44.11g C3H8/25.00g C3H8 = 132.03g CO2/x
x = 74.83g CO2
132.03g CO2/3 mols CO2 = 74.83g CO2/x
x = 1.7 mols CO2
2 HCl + Mg(OH)2 —-> MgCl2 + 2 H2O
How many grams of MgCl2 will be produced if there’s 1 mol of HCl?
2 mol HCl/1 mol HCl = 1 mol MgCl2/x
x = 0.5 mol MgCl2
95.20g MgCl2/1 mol MgCl2 = x/0.5 mol MgCl2
x = 47.60g MgCl2
4 NH3 + 5 O2 —–> 4 NO + 6 H2O
When 1.20 mole of ammonia reacts, what is the total number of moles of products formed?
4 mol NH3/a.20 mol NH3 = 10 total moles of products/x
x = 3
