Key Concepts in Titration Accuracy and Validity for Chemistry Students

Why should a controlled variable remain unchanged

To prevent it from influencing the results

To ensure my investigation was valid and that any changes in titre were caused only by the variable I was testing.

What are the results when you add too much phenolphatlein

Side reaction and increase or decrease in Ph level.

What happens if a side reaction occurs or increase or decrease in the Ph level in the solution.

Change the endpoint ---> the titre amount of NaoH required

The time of the light pink colour change

Too much indicator causes

my results to vary - inaccurate ----> invalid

Reduce the accuracy of and validity of my investigation

Too few indicator would make it difficult to

spot the light pink colour change which makes it harder to_________

get the precise endpoint

the results will be inconsistent and less accurate

What happens when you control the amount of indicator

My investigation were more valid since calculation and easurements were more likely to be accurate

why are my calculation and measurement accurate

The endpoint ocurred under the same conditions each time

What happens if there are other chemical/water present

Dilute or alter the concentration

Final concentration can be altered when there's _______in the burette or pipette

contaminants

What could result from contaminants in the burette or pipette

Inaccurate titre values -----> reduce consistency between trials

Why do you not wash the conical flask with chemicals

Keep CH3COOH pure for titration.

What happens if you wash conical flask with chemicals

change the concentration of the Ch3COOH -----> inaccurate titre

Controlling the washing procedure ensured...

same concentration each time

Improving accuracy and validity

What happens to the investigation by keeping the same equipment and why

The investigation stayed consistent

Because errors were the same for each trial

consistent investigation as same error each trial help__________

Help me to get concordant and accurate results ----> improve precision and help me obtain concordant titres

Concordant titres and imrpoved precision strengthens

What part

Glassware conclusion

accuracy and validty of my results

What did I do to address the issues caused if I didn't dilute the vinegar

Diluted the vinegar by a factor of 12.5

What does diluting by a factor of 12.5 meant

Pipetting a 20ml of the original CH3COOH into a 250ml volumetric flask, and making it up to the mark with distiled water.

After you have explain what diluting by a factor of 12.5 meant what have you produced?

A new titre of approximatley xyz ml ( 150ml/12.5 = xyzml)

which falls comfortably within the ideal titre range.

What do you need to point out when comparing dilution factors

An unavoidable equipment manufacturing error of 0.1ml in each.

After you have provide the calculation for the dilution factor, what should you write about

Conclusion

This calculation proves my point. With a lower %error....

What happens when you have a lower percentage error

The experiment will have less error and hence be more accurate and more valid

What needs to be said when you are concluding for your modification

State that these modifications I made will redue the errors in my investigation which improves my accuracy and support a more valid investigation,

Reuced erorr =

Improved accuracy and more valid investigation

What happens OVERTIME when the product was exposed to air

allows ingredients to evaporate ------>

What are the possible reasons for conclusion

- Improper storage

- Product mislabelling

- Errors made during the calculation or formulation of the product