Chemistry EEI

One week ago, I began my investigation where I am determining which concentration of Potassium Nitrate will optimize tomato plant growth. I began this investigation by calculating the different concentrations that I would test by using the following formula and its inversions:

Moles = mass (grams) / atomic mass units

Using this formula and it's inversions, it can be determined:

The Amount of Potassium Nitrate required for 350mg of Potassium:

            KNO₃ = 39.1 + 14.01 + 16 x 3

                        =  101.11 amu

            % of K in KNO_{3­ ­}= 39.1 / 101.11

                                    = 38.67%

            Mass of K in 1 mole of KNO₃ = 101.11 x 38.67%       

                                                             = 39.1g

           x mg of KNO₃ = 350 mg of K

           x = 101.11 x 350 / 39.1

           x  = 907.40

Therefore 907.40mg of KNO₃ will supply 350mg of Potassium

I performed the same equation 5 more times, substituting 350mg of Potassium to 200mg, 250mg, 300mg, 400mg, and 450mg to vary the concentration of Potassium in order to determine the optimum concentration for maximum growth. 

On Thursday the 26th of July, I begun the experiment by labeling all my 15 cups and lids. I also completed my calculations and to determine the 6 different masses of Potassium Nitrate. These masses were measured and collected in labelled containers. 

The next day, Friday 27th of July, I had made my solutions for my plants. The solution was made by simply adding the masses of Potassium Nitrate into 1 liter of distilled water and then dissolved. 500ml was taken out of the solution and was equally divided into 2 cups. This process was repeated 6 times so that there were 6 pairs of varied concentrations. This leaves 3 empty cups left from the starting 15. The 3 remaining cups were used as controls, and were filled with 250ml of distilled water per cup. 

Monday, the 30th of July, I received my 15 tomato plants. These plants were still planted in soil so I had to gently and carefully remove the soil from the roots of the plant. I used my hands to gently scrape the soil from the roots washed any remaining soil by dipping the roots into a beaker of distilled water. Once I had cleaned all 15 of my plants, they total lengths, root lengths and stalk lengths were measured and recorded into a table. Once this process was complete the plants were delicately placed into the cups containing the distilled water and concentrations of Potassium Nitrate, and were supported by the lid so that they could stand upright. After that, the plants were carefully placed near a window so that they could access UV light. The plants were left overnight and their growth would be measured once every 2 days. 

Tuesday, the 31st of July, I checked if my plants were in stable condition and if and major changes occurred. My plants seemed like they were doing fine and no one had tampered with my experiment. No data was recorded on this day.

Wednesday, 1st of August, Day 3, my tomato plants were measured to see if they grew or not. Results were recorded in a table. In general, all my plants grew about 0.5cm to 3cm within the last 48 hours. This is a positive indication that my hydroponic system is functioning properly.

Today, Thursday, 2nd of August, my plants were inspected for any major or significant changes in their well being (e.g. if plants had bugs on them, if anyone had spilled any of my solutions, if anyone has tampered with my experiment, etc).