A liquid may be an acid, base or neutral. The pH scale can be used to measure how acidic or basic a solution is. The scale is divided into three areas: Acid (readings below 7), neutral (reading of 7), and basic (readings above 7). Each division either increases or decreases the pH of a substance 10 times. The pH of 5 is ten times more acidic that a pH of 6. Water has a pH of 7, but when it mixes with air, the suspended materials will either raise or lower its pH. Acid Rain is an example of this type of reaction.
To determine the pH of various substances and their effect on organisms in the environment.
The materials used in this lab were wide range pH paper with its corresponding pH chart, a spot plate, forceps, and 8 dropper bottles. Also used were soapy water, ammonia, lemon juice, cola, distilled water, pond water, vinegar, and baking soda.
Using a spot plate, place a couple of drops of each solution into the numbered wells being careful not to mix the solutions. In well 1 place the soapy water, in well 2 place the lemon juice, in well 3 place ammonia, in will 4 place cola, in well 5 place distilled water, in well 6 place pond water, in well 7 place baking soda, and in well 8 place vinegar. Next, pick up a piece of pH paper with forceps and touch the paper to the liquid in well 1 and remove it. Then, compare it to the color of the pH paper to the pH color chart. Record the pH on the data table. After that use a new piece of pH paper each time, and repeat the steps in determining the pH of each solution recording all of them on the graph.
- Which liquid had the lowest pH?
- Which of the liquids had the highest pH?
- Which of the liquids was closest to being neutral?
- If the pH of a sample was 3, how many times more acidic is it than a solution with a pH of 6?
- How might some correct the ph of a lake with a reading of 3?
Add a base
- What would be the pH of human blood?
- How does non-tearing shampoo work?
It’s neutral so it doesn’t irritate a person’s eye
- What would be the likely pH of acid rain?
- What industries in our area pump materials into the atmosphere to create a drastic change in rain water?
The paper mill
- List any substance that had a pH that would cause tadpoles and fish to die.
Lemon juice, vinegar, and soda
The pH paper that was used was old and it didn’t give and accurate reading so another pH tester was used to find out which pH’s were off.
Discussion and Conclusion:
All fish die if the pH is 4.2 or lower. By looking at the data table you can see that if a fish was placed in lemon juice, cola, and vinegar the fish would die. So if you own a fish farm and rely on fish for a living you would have to make sure the pH of the water is above 5 on the pH scale, if the water was going below 5 you would want to add a basic chemical so it would even out the water to around a pH of 6 or 7. Also if you went trout fishing and you noticed that you saw a lot of dead fish floating in the water and wanted to know what the cause of the trout’s death was you could check the pH of the water. If the pH of the water was below 6 and you knew that trout died when the pH is 6 you would know the cause of their deaths.