1. Acids are ionic compounds that release H+ when in contact with water. LABORATORY EXERCISE #3: Acids, Bases & pH
What is the effect of acids and bases on biological solutions?*
INTRODUCTION
It is important for organisms to be able to protect themselves from changes in internal and environmental pH. Any changes could disrupt metabolic activities. Organisms have developed ways in which to cope with these changes. Today you will look at how some biological materials can help moderate drastic swings in pH. Working with your bench mates, you will use a pH sensor attached to a computer to see changes in pH as you add acid or base to water, to biological buffers, and to several biological solutions. You will then share your information with the
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Read about pH in your textbook and online. In one paragraph, describe what is acid, base, neutralization, buffer, isotope, ion, anion and cation. Give an example of each. Click on “Introduction” in the interactive below to better understand acids and bases: https://phet.colorado.edu/sims/html/acid-base-solutions/latest/acid-base-solutions_en.html 2. Explain what the pH scale measures and the difference in concentration of H3O+ ions between pH 7 vs. pH 8 and pH 4 vs. pH 6.
3. Carefully read and run through this animation prior to answering question 4: http://www.chembio.uoguelph.ca/educmat/chm19104/chemtoons/chemtoons5.htm
4. Read and research about the carbonate buffer system in our blood and one of the additional buffers we will be using: citrate buffer in foods and the function of phosphate buffer in the internal fluid of cells. Remember to use credible sources and cite them in APA. In your research you should be able to elicit the following:
a. Chemical equation involved (which part is the acid and which part is the base)
b. How it functions as a buffer
c. Its physiological or functional importance
5. Complete the Line and Scatter Graph Practice
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Use different colors for the different solutions, use a different symbol for each solution, and provide a legend. Graphs should be done by hand. (For example, circle each point in line 1, square each point in line 2)
● The graph should include the data for each of the solutions with acid added and with base added.
1. What is the independent variable?
2. What is the dependent variable?
SUMMARY QUESTIONS – Be sure to answer all parts of every question.
3. Describe the effect of adding HCl (acid) to each solution.
a. Does adding acid have a noticeable difference between solutions? Why or why not would you see differences/similarities? Cite specific evidence from your results.
4. Describe the effect of adding NaOH (base) to each solution.
a. Does adding base have a noticeable difference between solutions? Why or why not would you see differences/similarities? Cite specific evidence from your
An acid is a compound that donates hydrogen ions when dissolved in water. A base is a compound that releases hydrogen ions when dissolved in water. When an acid and base are mixed together, they neutralize each other, forming a salt and water.
Introduction: Everyday household items can be seen as just “household items”. However, it is often not realized that we could actually determine the pH very easily. It could also be important to know the pH in everyday life. For example, it is important to keep track of human pH levels. Some people are curious to see the pH of their own body, which is a great use to keep acidic levels leveled. Another use in real life is determining the pH of pools. Whether it’s your own or a public pool, pH indicators come in hand to make sure the pool is sanitary and safe. pH indicators are indicators that contain halochromic synthetic compound which is added to a solution so that it can be
In this assignment you will be asked to rank aqueous solutions of acids, bases, and salts in order of increasing pH. This is most easily done by first identifying the strong acids that have the lowest pH, the strong bases that have the highest pH, and the neutral solutions that have a pH near 7. The weak acids
To start out this study the difference between acids and bases has to be identified. Acids have very low pHs and have a high concentration of hydronium ions, while bases have a high pH and have a high concentration of hydroxide ions. The difference between strong bases and acids, and weak bases and acids is the amount of dissociation. Strong bases and acids dissociate a large amount and let go of their ions in solution, while weak bases and acids may only let go of some of their ions. This is important because if the unknown solutions aren’t strong acids or bases then using their ions to calculate the pH of the solutions will give false results (Diffen 2012).
Bases are a substance with a pH higher than 7, and have a high concentration of hydroxyl ions. Bases can react with acids in order to neutralise them in order to form salt and water. Bases are normally metal oxides or metal hydroxides. Sodium hydroxide for example is a base.
1. Describe the graph of pH values over the course of the reaction in Part II. Was the change in pH consistent over the course of the reaction? Do your best to explain the reason for the shape of the pH curve in your own words:
An acid is a substance which has an excess of H+ ions. Common characteristics of acids include tasting sour and reacting strongly with metals. The acid used in this lab was Hydrochloric Acid (HCl). A base is
In this experiment different pH levels ranging from 3 to 11 were used to test the effects on daphnia heart rate. The pH scale ranges from 0 to 14. A pH ranging from 0 to 6 is acidic, a pH of 7 is neutral, and a pH higher than 7 ranging from 8 to 14 is basic. PH revolves around hydrogen ions (H+). The reason pH levels can be acidic, basic, or neutral is because acids give hydrogen ions away while bases accept hydrogen ions. (Decelles, 2002).
Using Graph 1: The Volume of Titrant Added in order to reach the Endpoint and the Corresponding pH Values, observe the vertical line of each titration and see the points in which the horizontal lines intersect it. These points give the
The pH of a solution is the measure of the concentration of charged Hydrogen ions in that given solution. A solution with a pH lower than seven is considered to be acidic. A solution with a higher pH is a base. It is very important for organisms to maintain a stable pH. Biological molecules such as proteins function only at a certain pH level and any changes in pH can result in them not functioning properly. To maintain these constant pH levels, buffer solutions are used. A buffer solution can resist change to small additions of acids or base’s. A good buffer will have components that act like a base, and components that act like an acid.
The hydrogen ion (H+) concentration is extremely important to living organisms. Even small changes in H+ ¬¬ion concentration can cause serious consequences to the structural and functional integrity of molecules. Consequently, it is important to regulate the pH within strict limits so that important biochemical processes of living systems can proceed normally.
2. Following solutions are added to the tubes and the pH of each tube is determined:
An acid-base titration is the determination of the concentration of an acid or base by exactly neutralizing the acid/base with an acid or base of known concentration. This allows for quantitative analysis of the concentration of an unknown acid
If an acid-base disturbance shifts the pH outside of the physiologic range, various control measures are activated to resist the change in pH. Compensatory mechanisms try to preserve the normal 20:1 ratio of bicarbonate to carbonic acid to keep the pH at normal range. The body works to maintain normal ratios through a compensation mechanism using renal and respiratory methods (Crowley, 2010).
The acidity of a chemical is determined by how concentrated the chemical is with Hydrogen ions. This is describe in an example Loses H Gains H Alkaline solution Acidic Solution NH CHRCOO ç NH CHRCOO è NH CHRCOOH Overall Negative charge "Zwitterion" Overall Positive charge lost H so makes solution No change gained H so makes solution more acidic.