pH Lab Report - testing household liquids

Alyssa Bellave Living Environment

10/26/11 Mrs. Padilla

pH Lab

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 ...

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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:

Analysis:

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.

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.

Give one possible explanation why the pH value for the tap water being different from the pH value for distilled water.

Teacher Reviews

Here's what a teacher thought of this essay

Patricia McHugh

1st of Dec 2012

Awarded 3 stars as it is a good piece of work for this level. They could have used more scientific knowledge in their introduction to show their knowledge and understanding of acids and bases. The hypothesis has not been justified and there is no indication as to where they have got their predictions from. A good method is used and a good basic analysis of results. An improvement would be to refer to the results in the analysis and discuss if their hypothesis was proved correct or not. Shows some good understanding. It would be good to add in a section on any improvements they could make to their method.

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Peer Reviews

Here's what a star student thought of this essay

skatealexia

7th of Jul 2012

Quality of writing

Minor spelling mistakes present. Otherwise, spelling, grammar and punctuation seem okay.

Level of analysis

Good hypothesis although the scientific reasoning behind the experiment is not explained, although it is hinted at in the introduction. The method could be bullet pointed or numbered so it is clear where each step comes. The candidate gives a data table but I'm not sure if these are the results and the candidate does not state if these results correlated correctly with their hypothesis. The analysis is explained well, and explains why the experiment happened the way it did.

Response to question

Overall a good basic piece which understands the properties of acids and bases well for this level of qualification. The candidate explains why the different household substances have the properties they do in a chemical way. The candidate was wrong in some instances and did not justify their hypothesis or why they were wrong which should have been improved.

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