Introduction: Substances, even household substances, can be acidic, basic, or neutral. Acids and bases are called aqueous solutions, or mixtures of certain substances dissolved in water. The amount of acidity or basicity can be measured by using the pH scale. The scale runs from 1-14. The scale has to do with the amount of hydrogen ions [resent in a substance. Hypothesis: Our hypothesis for this experiment consists of twelve different substances.
The tomato juice will be acidic; the distilled water will be neutral; the Windex will be basic; the vinegar will be basic; the soda will be basic; the milk will be neutral; the buttermilk will be neutral; the baking soda solutions will be acidic; the “green” cleaner will be basic; the household cleaner will be acidic; the Lemon Juice will be acidic.
Materials: For this lab we need pH paper, a spot plate, water (distilled, if available), and substances with varying pH. Safety: In this lab we must were goggles and aprons to avoid skin contact with all chemicals that are going to be used in this experiment.
If it does happen, we must report any skin contact or chemical spills to our instructor immediately. Procedure: First we get a spot plate and put three to four drops of each liquid substance in each of the wells. The liquid must correspond with the label on the spot plate to avoid contamination. Then we test each substance using the pH paper. The color of the part of the paper that was dipped in the substances was then matched with the indicator colors.
After we test each substance, we recorded the data in a data table. Data Table: Substance pH Value Acid, Base or Neutral.
Tomato Juice 4 Acid Distilled Water 6 Acid Windex 9 Base Vinegar 2 Acid Soda 4 Acid Milk 7 Neutral Buttermilk 5 Acid Baking Soda Solution 9 Base “Green” Cleaner 7 Neutral Household Cleaner 10 Base Lemon Juice 3 Acid Tap Water 6 Acid Analysis: 1. ) The pH scale is a measure of the concentration of which ion? * The pH scale is a measure of the concentration of the Hydroxide ion. 2. ) Briefly describe the different properties of acids and bases. * Acids have the lowest pH values or less than 7 on the pH scale. They have the highest concentration of hydrogen ions.
The high concentration of these ions gives acids their properties like sour taste. Acids damage living tissue by causing burns upon contact. Bases, however, have the highest values or greater than 7 on the pH scale. They have the lowest concentration of hydrogen ions. Bases have higher levels of hydroxide ion, which gives bases their identifying properties, such as bitter taste and slippery feel. Bases damage living tissue by dissolving it upon contact. 3. ) Give one possible explanation why the pH value for the tap water being different from the pH value for distilled water.