Question
An experiment is planned to record the change in pH as a powdered base is added to 50cm^3 dilute hydrochloric acid The method suggested is step 1 add dilute hydrochloric acid up to the 50cm^3 mark on a beaker; step 2 add one spatula of the base and stir; step 3 measure the pH of the mixture; step 4 repeat steps 2 and 3 until the pH stops changing. (i) State how you could change the method so that the amounts of dilute hydrochloric acid and of the base can be measured more accurately. dilute hydrochloric acid __ base __
Answer
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Ulysses
Professional · Tutor for 6 years
Answer
To measure the dilute hydrochloric acid more accurately, use a graduated cylinder or a burette instead of a beaker. To measure the base more accurately, use a balance to weigh the exact amount of base to be added each time. To measure the
more accurately, use a calibrated pH meter instead of pH paper. To ensure the accuracy of the repeated steps, thoroughly stir the mixture before each pH measurement.
Explanation
## Step 1: The first step in the experiment is to add dilute hydrochloric acid up to the
mark on a beaker. To increase the accuracy of this measurement, we could use a graduated cylinder or a burette, which have more precise volume markings than a beaker.## Step 2: The second step involves adding one spatula of the base and stirring. To increase the accuracy of this measurement, we could use a balance to weigh the exact amount of base to be added each time. This would ensure that the same amount of base is added in each iteration of the experiment.## Step 3: The third step is to measure the
of the mixture. To increase the accuracy of this measurement, we could use a calibrated pH meter instead of pH paper. A pH meter provides a digital readout, which is more accurate than the color comparison used with pH paper.## Step 4: The fourth step is to repeat steps 2 and 3 until the pH stops changing. To increase the accuracy of this step, we could ensure that the mixture is thoroughly stirred before each pH measurement. This would ensure that the base is evenly distributed throughout the mixture, providing a more accurate pH reading.