Gas Density

This week, we took last week’s main focus of density and incorporated it into this week’s lesson. After learning that the formula for density is p=m/v, and testing the idea on matter and water, we learned how to graph this information. The mass is the dependent variable; this means the data goes along the y-axis. The volume is the independent variable; this means the data goes along the x-axis.  The slope of the graph is described as the density (change in y/change in x).

Once we learned this concept, we applied this idea to gas. We did this through doing a Gas Density lab. The objective of this lab was to extract gas from the chemical reaction of Alka-Seltzer and water and calculate the resulting density. The procedures we took for this lab were fairly simple and easy to follow. First we put 1-2 pieces of Alka-Seltzer in a cupcake tin and a bottle with filled some water and took the mass of both subjects. My table groups resulting mass (before) was 71.44g. After recording the mass, the top was placed onto the bottle and connected to a thin blue tube. This blue tube was connected to a larger bottle of water which was placed upside down in a large bin of water. Once everything as put into place, a table member of mines cautiously shook up the water to create a reaction with the Alka-Seltzer. I observed as the gas rose to the top and through the blue tube. When this happen, the water level in the larger bottle of water began to decrease. Once my group and I were sure the reaction had fully ceased, we unconnected the thin blue tube from the bottle mixed with water and Alka-Seltzer and weighed its remaining mass. The remaining mass was 71.27g. With this, we were able to calculate the mass of the gas which was –0.413g (71.44-71.27). Since the objective was to the find the density, we still have to calculate the volume. We took the rest of the liquid and poured it into a cylinder and found it was 338mL. Using the formula for density and significant figures, we calculated the density of gas to be 0.00121g/mL. This was interesting because we noticed that it was 600 times less dense than water.

This week we learned how to find the density of gas and the correct procedure toward doing so. I found it very interesting and a simple concept to understand. I think I have all of the concepts to a fair understanding but once doing a worksheet or taking a test, I seem be a little bit confused once receiving my results back. Personally, I think from 1-10, my understanding of this week's lesson is an 8 or 9. Hopefully, it will show in this upcoming unit test because I feel pretty confident about the main ideas.