Ingrid's Day 9 Sr.Project

Ingrid Wu's Day 9 Blog

May 17 2023

What type of relationship is the Carbon Dioxide decrease in the machine with KOH?

As the test I did with Ca(OH)2, I set up a similar test for KOH to see whether the decrease of CO2 in the box is also exponential. As I suspected, the relationship is similar. However, conducting tests with KOH is easier for me because of its properties. KOH is soluble in water, so it won't precipitate and affect the test result. 

I set up three trials with different amount of KOH in 2L of water: 5 grams, 10 grams, 15 grams. I checked the CO2 sensor every 5 minutes until the level went down to 201 ppm, which is the known minimal value that the CO2 sensor can detect. 

I got the following data: 

Through the data, we can see that the drop of CO2 level is more significant when there is a bigger amount of KOH, when the initial level is approximately the same. 

When I plugged them in the Desmos, the exponential decay is more obvious:

Three curves from top to bottom correspond to 5 grams, 10 grams, and 15 grams trials. Following the curve, we can see that the change of CO2 level is the most significant during the first 10 minutes period, the initial level is almost the same. Also, the rate of change is more obvious on the purple line (purple > red > green). Therefore, we can say that there is a exponential relationship between the time and the CO2 level when KOH is used, and more KOH in the 2L of water will decrease the CO2 level faster, especially in the first 10 minutes. 

 

Total hour: 64h

work hour: 8h