L4: PH

L4: PH

1. Introduction

The ph is a measure of the acidity or basicity of a solution. Solutions with a PH less than 7 are said to be acidic and solutions with a PH greater than 7 are basic. AAnd the solution that have a pH 7 are neutral.

Equation for following PH:                 pH= -log (H+)

For mesuring the PH of a solution at the lab we have different pH indicators:

- Universal indicator paper: this method consists as a continous colour change from about pH 2 to pH 10.

- pH- meter: It consists of a glass electrode connected to an electronic meter that measures and displays the pH reading.

2. Objectives

•  Measure different pH values of organic and inorganic solutions.

•  Prove different methods of measuring pH

3. Hypothesis

If the solutions are more big than 7, it will be a basic concentration and if the solutions are more little than 7, it will be acidic concentration.

4. Material

• Distilled water
• Milk
• Wine:  red or white
• Lemon
• Tomato
• Coffee
• Carbonated beverage
• 10% NaOH solution
• 10% HCL solution
• NH3 solution
• Soap solution

• Universal indicator paper (strips)
• pH-meter
• Acetic Acid
• Tongs
• 8x100 ml Beakers
• 2 clock glass
• 1x250 ml Beaker
• 5 test tube rack
• 10 ml Pipet
• funnel
• graduated cylinder

5. Process

First of all, we took three beakers and three glasses clock. 
Squeeze the lemon and tomato and put ens their respective beakers. 
We took a piece of indicator paper and put it in the solution for 20 seconds. 

when removing the strip we saw that each had a different color. I compared it with a flag color according to the color and had a basic or acid concentration.

After of all, we squeeze the rest of the lemon inside a beaker and filter the solution with a funnel and cellulose paper.

We prepared a test tub rack with 5 test tubes cleaned with distiller water. We marked the tubis with the labels: A, A1,A2,A3, and B.

We added 10 ml of lemon juicxe to tubes A and B and took the A tube and put 5ml of its lemon juice to test tube A1. Took the A1 tube and put 2,5ml of its lemon juice to tube A2 and the A2 we took it and put 1,2ml of its lemonjuice to tube A3.
We added distilled water to each test tube until it has the same volume as test tube B (10ml).

We calculated the concentration of each test tube with the formula we have below:

               Concentration (%) = (volume of juice / total volume) · 100

6. Observations

We observe that our hypothesis had been proven since the solutions of the strips out of the correct color, according to its degree of acidity or whether it was more basic.

• Acidic concentration: HCl(pH=1) , vinegar(pH=3) , wine white(pH=3) , tomato(pH=4), coffe(pH=6), milk(pH=6).

• Neutral concentration: ditillated water (pH=7)

• Basic concentration: soap(pH=10), NaOH(pH=14)

7. Conclusions

My conclusion is that the hypothesis has been confirmed, since the solutions have come out with the proper pH.

8. Questions

Which of the solutions gave and acid pH?

Acidic concentration: HCL(pH=1) , vinegar(pH=3) , wine white(pH=3) , tomato(pH=4), coffe(pH=6), milk(pH=6).

Which of the solutions was alkaline?

Basic concentration: soap(pH=10), NaOH(pH=14)

Which of the solutions were neutral? Did you expect these results? Explain.

Neutral concentration: ditillated water (pH=7)

Yes, i did. Because the distillated water we used to clean the concentrations that we remaining neutral.

How does a pH of 3 differ from pH of 4 in terms of H+ comcentrations?

Concentration becomes more basic.

In the second part of the experiments, you have compared the pH of the same product in different comcentrations, In this case explain:

                       a) Which is the dependent variable?

                        concentration can't vary alone.

                        

                       b) Which is the independent variable?

                          concentration can vary alone.

                       c) Which is the problem that we want to solve?

                          we equalize the concentrations

                       d) Which is the control of the experiment?

                         The control is the tube B

                       e) Write the results and conclusions of your experiments

                          

                         At finally concentrations of lemon and distilled water are matched.

 Which pH do you think that gastric juices might have? why? Do you think that intestinal pH has the same pH? why?

Has an acid pH, as it serves to digest the food you eat and to digest. 

Yes, because all are.

 Which Ph do you think that blood might have? why?

Neutre concentration, because it would have red blood hypotonic or hypertonic media and the globule is deformed or inflate to match the concentrations.

 What is acid rain? which are the consequences in the ecosystems and how is its formation pattern? is rain in Barcelona acid or alkaline?

Acid rain is formed when moisture in the air combines with nitrogen oxides, sulfur dioxide and sulfur trioxide emitted by factories, power plants, boilers and vehicles that burn coal or petroleum products containing sulfur. In interaction with the rainwater, these gases are nitric acid, sulfuric acid and sulfurous acid. Finally, these chemicals fall to the ground accompanying the precipitation, forming acid rain.

Is alkaline.