LAB #4 - CARBON CYCLE

Introduction to the Carbon Cycle





CXHYOZ + O2CO2 + H2O + energy

The equation above describes the process of carbon dioxide being released into the atmosphere. A hydrocarbon reacts with oxygen to form carbon dioxide, water and energy.  This reaction occurs in a number of settings:
  1. Respiration performed by plants and animals where glucose is the starting hydrocarbon. 
  2. Fungi and bacteria break down dead animal and plant matter and convert the carbon into carbon dioxide. 
  3. Combustion of organic material such as wood and fossil fuels. 
  4. At the surface of the oceans where the water becomes warmer, dissolved carbon dioxide is released back into the air. 
Carbon dioxide is removed from the atmosphere a number of ways including:
  1. Plant photosynthesis converts CO2 into glucose and energy. 
  2. At the poles of the earth, surface temperature of oceans decreases. CO2 solubility increases at cooler temperatures, thus removing some CO2 from the atmosphere. 
Fungi and bacteria breaking down the dead material accounts for a staggering 90% of all carbon returned to the atmosphere. Second, the burning of fossil fuels releases nitrate as a byproduct and nitrate is a plant nutrient. 

This is a 3 part lab as described below:

PART 1: STANDARDIZATION OF NaOH   (Practice Technique & Set-Up)

  • You will perform a number of titrations to learn and practice titration techniques. 
  • You will standardize the titrant (NaOH) which will be used later on. 
In titrations, sodium hydroxide (NaOH) is commonly used to determine the concentration of an unknown acid.  We say the NaOH solution is a standard solution.  Standardized solution are solutions where the exact concentration is known. Preparing a standardized solution of a particular concentration is actually somewhat problematic for two reasons:  First, solid NaOH absorbs a significant amount of water from the air.  Solutions that do this are said to be hygroscopi

PART 2:  ANTACID ANALYSIS   (Introduced to Back Titration & Standard)

  • You will analyze an antacid to determine how effective it is at neutralizing acid, using your new found titration techniques.
    You will learn about indirect method of measurement. 
More here. 


PART 3: SELECTIVE PRECIPITATION AND LEAF JAR ANALYSIS

  • You will determine which chemical to use in a reaction to get a desired precipitate. 
  • You will use your titration skills to quickly and effectively titrate a solution to determine its composition. 
  • You will analyze a set of experimental jars to determine how much CO2 decomposing leaves release into the atmosphere.
More here.