Sunday, September 15, 2013

Acid and Bases Lab


        In the environment, organisms need to be able to keep a stable ph to survive, even if changes occur. This lab tested that. The purpose of this lab was to see which material out of the ones provided was the best buffer of ph. The amount of acid and base added to the materials was the independent variable while the ph of materials once the acid and bases was added was the dependent variable. Acids and bases were used in this experiment. An acid is a solution with a ph of 6 or lower. When an acid is added to something, the hydrogen ion concentration is increased. On the other hand, a base is a solution with a ph of 8 or higher. When a base is added to something, the hydrogen ion concentration is reduced. After the experiment was conducted, the total buffer range was calculated. A buffer is a solution that minimizes change in ph when acids or bases are added to it, so the total change in buffer range would be how much the buffer had to change to keep the level of acids and bases the same.  
       Lab groups first tested the buffer range with water. Two 20 ML beakers of water were available for use. One beaker was for the acid and the other was for the base. In one beaker of water, groups added acid in five drop increments. In the other beaker, they added base in five drop increments as well. Every time after the five drops were added,  they would measure and record the ph of the beakers. This was done until the materials each had a total of thirty drops of acid or base in the beaker. Then, the acid and base content were measured with ph probes that were hooked up to Vernier Lab devices. This device was used to graph, chart, and measure the ph of the beakers. Next, the ph of spinach was measured. This was done by using two 20 ml beakers full of spinach. Five drops increments of acid were added in one beaker and base in the other beaker up until thirty drops again. Once again, the Vernier Lab device and ph probes were used to measure the ph content.
Adding acid and base to orange juice. 

Class data table that recorded which material it was, level of ph after acid and base was added, change in ph, and total buffer range.


       Our hypothesis was that artificially altered substances would be the best buffers because they can be engineered to have specific buffer ranges and can be altered to be good buffers; however, this was proved wrong. The lower the buffer range the greater the capacity that substance has to absorb acid before the acid starts affect the specific substance. Our data shows that naturally living things are the best buffers. We tested orange juice (best buffer) and spinach. Orange juice had a buffer range of 1.24 and 0.41, and spinach had a buffer range of 0.44. This was significantly lower than substances such as buffered aspirin that had a buffer range of 4.05 and antacid (worst buffer) which had a buffer range of 7.36. There were outliers in the data. For example, one group concluded that the buffer range for buffered aspirin was 1.95, and another that the buffer range for orange juice was 7.99. We can identify this as incorrect because after research we learned that naturally living things must be good buffers. This is because they have to react appropriately to acids in their environments in order to survive. If oranges and spinach were bad buffers, they would instantly die when coming in contact with acidic materials. 
     Each lab table tested different biological materials to determine the buffer range of each substance. The answer to the main question of this lab was that spinach turned out to be the best buffer our class concluded. Because it had the lowest buffer range, which is ideal, spinach's pH barely changed at all.

References: 





1 comment:

  1. To help the reader, please work on including sections (ie. Purpose, Hypothesis, etc) it will make the reading of your lab report flow more smoothly. In addition, please make sure your change the names of the contributors to have your real names show up. You can change this in the settings tab of your blogger profile. Thanks!

    ReplyDelete