pH LabpH LabpH LabpH LabTitle your paper!Title your paper!Title your paper!Title your paper!

pH Lab pH Lab pH Lab pH Lab

Purpose: Purpose:

To measure the pH of common household To measure the pH of common household

products. products.

To investigate and understand an acid and a base as well as the effects acids and bases have on the environment and the body. 

Background Background InformationInformationBackground Background InformationInformation

An acid is a compound that will produce H+ in solution (meaning the compound has H on the front and will give the

H up when placed in H2O).

A base is a compound that will produce OH- in solution (meaning that the compound has OH on the end and will

give the OH up when placed in H2O).

We measure the acidity of a substance using the pH scale. The pH scale is divided into three essential parts; the acidic region, the neutral region, and the basic region. 07 is considered acidic. 7 is neutral and 714 is basic.

Background Background InformationInformationBackground Background InformationInformation

Exposure to some acids or bases can cause harm to the human body whereas some acids and bases are used as cosmetics, cleaning materials, and even foods. Acids and bases can also have an effect on our environment. The disposal of these chemicals is critical to the health of the ecosystem around us. In this lab we will explore acids and bases and identify how these compounds affect both living and nonliving things as well as the health of our water systems.

Household Product

Prediction pH Acid, Base, or Neutral

Milk of Magnesia

Vinegar

Ammonia

Water

Record name of Record name of household product household product

here! here!

Record Record prediction prediction

here! here!

Is the product an acid, Is the product an acid, base, or neutral?base, or neutral?

Record pH here! Record pH here!

Liquid ProceduresLiquid ProceduresLiquid ProceduresLiquid Procedures1.1. RECORD the common household products in the table. RECORD the common household products in the table.

2.2. PREDICT if the liquids you will test will be acidic, basic or neutral. In the PREDICT if the liquids you will test will be acidic, basic or neutral. In the

table, record your prediction. table, record your prediction.

3.3. COLLECT DATA by testing each of the liquids at your lab station. COLLECT DATA by testing each of the liquids at your lab station.

4.4. Place 4-5 drops of each solution in a separate well. Remember which Place 4-5 drops of each solution in a separate well. Remember which

solution went into which well.solution went into which well.

5.5. Each team member will be given one pH strip to test ONE solution. Only Each team member will be given one pH strip to test ONE solution. Only

1/2 of the pH strip should be submerged.1/2 of the pH strip should be submerged.

6.6. Compare the color change to the pH scale and RECORD the pH of the Compare the color change to the pH scale and RECORD the pH of the

household product in the table below. household product in the table below.

7.7. Based on the pH determine if the household product is an acid, base, or Based on the pH determine if the household product is an acid, base, or

neutral and record it in the table below.neutral and record it in the table below.

No liquid ProceduresNo liquid ProceduresNo liquid ProceduresNo liquid Procedures

1.1. RECORD the common household products in the table below. RECORD the common household products in the table below.

2.2. PREDICT if the liquids you will test will be acidic, basic or PREDICT if the liquids you will test will be acidic, basic or

neutral. In the table below, record your prediction. neutral. In the table below, record your prediction.

3.3. Watch video about using red cabbage as a Watch video about using red cabbage as a pH indicator

4.4. Using Using pHet pH simulation, RECORD the pH of the common , RECORD the pH of the common

household products. household products.

5.5. Based on the pH determine if the household product is an Based on the pH determine if the household product is an

acid, base, or neutral and record it in the table below.acid, base, or neutral and record it in the table below.

pH ScalepH ScalepH ScalepH Scale

AnalysisAnalysisAnalysisAnalysis1. What is an indicator? Explain the indicator used in this lab.

2. Draw a pH scale and place each of the substances you tested in the appropriate spot. Predict where soda, milk, soap, antacids and lemon juice would be on the scale. 1 2 3 4 5 6 7 8 9 10 11 12 13 14

3. Why is it important for water to be neutral?

4. How could you increase or decrease the pH of water?

5. How would the pH of the groundwater be affected if large amounts of ammonia were dumped accidentally? Explain.

6. How would the pH of a stream be affected if car batteries were disposed of in the stream? How would this affect the aquatic life?

ANSWERSANSWERSANSWERSANSWERS1.Indicators are chemicals that show whether the

given solution is acidic or basic, by the sudden change of color. A universal indicator is a mixed indicator of organic chemicals which not only shows whether the given solution is acidic or basic, but also shows the approximate pH values by giving a wide particular color for a specific value of pH

IndicatorFinal colorAcid Alkali

Litmus Red BlueMethyl orange Pink YellowPhenolphthalein Colourless Deep pink

The three common indicators used in the laboratory are:

ANSWERSANSWERSANSWERSANSWERS

3. The pH of water determines the solubility (amount that can be dissolved in the water) and biological availability (amount that can be utilized by aquatic life) of chemical constituents such as nutrients (phosphorus, nitrogen, and carbon) and heavy metals (lead, copper, cadmium, etc.).

For example, in addition to affecting how much and what form of phosphorus is most abundant in the water, pH also determines whether aquatic life can use it. In the case of heavy metals, the degree to which they are soluble determines their toxicity.

4. By adding a few drops of alkali to pure water, it's pH increases; and by adding a few drops of an acid decreases the pH of pure water.

ANSWERSANSWERSANSWERSANSWERS

Now, you figure out 5 & 6 Now, you figure out 5 & 6

Groundwater Groundwater Pollution Lab Pollution Lab Groundwater Groundwater Pollution Lab Pollution Lab