Measuring the pH of Common Household Substances

CAT - Measuring the pH of common household substances 1. Predict the pH value of substances & estimate the pH value by using the universal indicator. 2. Use the indicator to identify acidic, basic, and neutral substances found in any home 3. Classify household items as acids and bases 4. Collect organise and analyse results in tables and graphs (if necessary) 5. Analyse results and explain the reason the substances have the pH obtained.

Aim – To use a universal indicator to measure the pH of various household substances and to identify acidic, basic and neutral substance.
Hypothesis: I hypothesise that food substances such as coke and vinegar will be acidic, whilst cleaning products such as detergent and diluted hydroxide acid will be basic.
Independent variables: Household solutions
Dependent variables: pH level
Controlled variable: Universal indicator

Materials: * Universal indicator * Spotting tile * pH chart * Detergent * Vinegar * Coke * Diluted Hydrochloric Acid * Sucrose * Sodium Bicarbonate * Sodium Hydroxide * Apple juice * Paper and pen

Method :
1. The household substance was added into each spotting tile.
2. One or two drops of the universal indicator was added to the household substance.
3. Using a pH chart, the results were analysed.
4. This process was repeated for all household substances.
5. All results were recorded.

Results: The pH values of household substances: Substances | pH level | Detergent | 7.0 | Vinegar | <4.0 | Coke | <4.0 | Diluted Hydrochloric Acid | <4.0 | Sucrose | 7.0 | Sodium Bicarbonate | 8.5 | Sodium Hydroxide | 8.5 | Apple Juice | <4.0 |

The food substances are acidic and the cleaning substances are basic.

Discussion
The food products were all acidic and had the same pH levels of 4.0, except sucrose had a higher pH level of 7.0. The other food products have a pH level of 4.0 because food products contain a lot of hydronium ions and the acids in food are used to preserve food. Sucrose had had a higher pH level because the water the sugar was dissolved in doesn’t change the pH of the solution. The household cleaning products were both basic and neutral. The sodium bicarbonate and the sodium hydroxide had a pH level of 8.5 and the detergent had a pH level of 7.0. Detergent has a pH level of 7.0 because detergent is a base, so it neutralises acids. Detergent dissolves grease and it is soluble in water.
Some errors that occurred were that there was a different amount of drops in each substance, therefore which could make the results not accurate. In the future, we should make sure that there is a same amount of drops in each substance so that our results and outcomes will be more accurate. Also, there were some errors when comparing the universal indicators results to the pH chart. The group would be unsure about the shade of red or blue, so a lot of mistakes could have potentially have been made.
If someone wanted to use a pH test kit to test out the pH of something but they had no universal indicator or litmus paper, you could use the red cabbage indicator. You extract the colour from the red cabbage and make your own litmus paper.

Conclusion
In conclusion, the results from this experiment support my hypothesis because the food products were indeed acidic and the household substances were basic. It is important to know the pH of household substances because if the pH level is too high or too low, it can become harmful towards the body.

Anna Phung

Assessment Rubric Name________________________

CATEGORY | 4 | 3 | 2 | 1 | Experimental Hypothesis | Hypothesized relationship between the variables and the predicted results is clear and reasonable based on what has been studied. | Hypothesized relationship between the variables and the predicted results is reasonable based on general knowledge and observations. | Hypothesized relationship between the variables and the predicted results has been stated, but appears to be based on flawed logic. | No hypothesis has been stated. | Materials | All materials and setup used in the experiment are clearly and accurately described. | Almost all materials and the setupu used in the experiment are clearly and accurately described. | Most of the materials and the setup used in the experiment are accurately described. | Many materials are described inaccurately OR are not described at all. | Procedures | Procedures are listed in clear steps. Each step is numbered and is a complete sentence. | Procedures are listed in a logical order, but steps are not numbered and/or are not in complete sentences. | Procedures are listed but are not in a logical order or are difficult to follow. | Procedures do not accurately list the steps of the experiment. | Results | Professional looking and accurate representation of the data in tables and/or graphs. Graphs and tables are labeled and titled. | Accurate representation of the data in tables and/or graphs. Graphs and tables are labeled and titled. | Accurate representation of the data in written form, but no graphs or tables are presented. | Data are not shown OR are inaccurate. | Discussion | Discussion is evidence-based citing the data, refers back to purpose and indicates acceptance or rejection of the hypothesis. Defines the outcome of the investigation. Possible sources of experimental error stated | Data is interpreted and specific information is cited to analysis but may not refer back to the purpose, question or problemInterpretation of data does not clearly determine if hypothesis is supportedSource of error is cursory such as human error and does not show a valid attempt at resolving this type of error in future laboratory work. | Data interpretation is cursory with no attention to the data or citations, trends and relationship to the original objectives and hypothesis are missingSome mention of issues encountered and ways to improve on the experiment are given but reflection is confusing and may not relate to the outcomes determined | Data interpretation is cursory with no attention to the data or citations, trends and relationship to the original objectives and hypothesis are missingNo mention of issues encountered or ways to improve the experiment. | Scientific Concepts | Report illustrates an accurate and thorough understanding of scientific concepts underlying the lab. | Report illustrates an accurate understanding of most scientific concepts underlying the lab. | Report illustrates a limited understanding of scientific concepts underlying the lab. | Report illustrates inaccurate understanding of scientific concepts underlying the lab. | Conclusion | Conclusion includes whether the findings supported the hypothesis, possible sources of error, and what was learned from the experiment. | Conclusion includes whether the findings supported the hypothesis and what was learned from the experiment. | Conclusion includes what was learned from the experiment. | No conclusion was included in the report OR shows little effort and reflection. | Participation | Used time well in lab and focused attention on the experiment. The group had at least 4 items to investigate. | Used time pretty well. Stayed focused on the experiment most of the time. The group had 3 or 2 items to investigate. | Did the lab but did not appear very interested. Focus was lost on several occasions. The group had 1 item to investigate. | Participation was minimal OR student was unreceptive about participating. The group did not bring any household substances. | Spelling & Grammar | One or fewer errors in spelling, punctuation and grammar in the report. | Two or three errors in spelling, punctuation and grammar in the report. | Four errors in spelling, punctuation and grammar in the report. | More than 4 errors in spelling, punctuation and grammar in the report. |
Total marks / 36