Can u help me to answers this question 5. Calculate a relative standard deviatio

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Can u help me to answers this question 5. Calculate a relative standard deviation (RSD) for the standardization trials: RSDe (sh) × 100%. (RSD has units of %) RSD Calculation of Sulfuric Acid in Battery Acid 6. Show the cakculation of the concentration of H,SO, in the diluted battery acid that you were given. [H,SO,| in diluted battery acid Calculate the original ,SO,] in the undiluted battery acid, assuming that it was di- luted 1:5. 7. [H,SO] in original undiluted battery acid "-- Error Analysis Discuss two possible sources of error in the experiment. You should discuss the sources of error, how they might affect the experiment, and suggest a modification by which it can be removed. Where possible, use your data to support your statements. Please note that you must be specific; "human error" or "equipment error" are unacceptable. QUESTIONS Answer these questions on a separate sheet of paper. 1. Titrations are considered a highly precise analytical method, usally with RSDs well 27 below 1.0%. Based on the size of your RSD value, what would you say about your preci- sion? Explain.(Use your results to support your answer) Why was it necessary to standardize the NaOH solution before the battery acid titra- 2. 3. 4. 5. A discharged battery may be recharged by feeding electrical current back into the bat tion? What is the difference between the equivalence point and the end point of a titration? Why was it necessary to dilute the battery acid before titration? tery. A ful ll charge restores the chemical difference between the plates and leaves the battery ready to deliver its full power. Write an equation for the reaction that occurs when a battery is being recharged.

Explanation / Answer

1)

If data values are all equal to one another, then the standard deviation is zero.

If a high proportion of data points lie near the mean value, then the standard deviation is small. An experiment that yields data with a low standard deviation is said have high precision.

If a high proportion of data points lie far from the mean value, then the standard deviation is large. An experiment that yields data with a high standard deviation is said to have low precision.

2)

standardization is a method in which the concentration of a solution which would be used in the experiment to determine the concentration of another solution is confirmed.

Here, NaOH is used to determine the amount of battery acid present. Thus, the exact molarity of NaOH must be known to determine the exact amount of acid it is reacting with here. Thus standardization of NaOH is done in the experiment prior to its use.

3)

equivalence point --> the point in which there is exactly mol of base = mol of acid, or equivalent amounts

end point of titration --> it is the point in which we experimetnally finish the titration due to a pH change in the titration. Note that for some indicators, the pH range is broad, so it will not be exactly as the equivalence point

Typically, the endpoint is a and must be a good approximation to the equivalence point

4)

Battery acid is very strong acid and it will carry plenty of acid molecules per unit volume. So when we get a drop in the solution, the pH might change drastically, making it hard for us to have a precision in the euqivalenc epoint.

Therefore, dilution favours that, experimetnally, the volume we add is larg eneough so we can see the equivalence/end point clearly

5)

The following reaction occurs when a battery is being recharged,

PbSO4 (s) + 2 H2O (l) --------------> PbO2 (s) + Pb (s) + 2 H2SO4 (aq)

The following reaction occurs when a battery is being discharged,

PbO2 (s) + Pb (s) + 2 H2SO4 (aq) -----------------> PbSO4 (s) + 2 H2O (l)

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