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jolli1 [7]
3 years ago
7

A water treatment plant needs to maintain the pH of the water in the reservoir at a certain level. To monitor this, they take 2

oz. of water at 37 locations every hour, measure the pH at each of those locations, and find their average. If the pH level of the reservoir is ok, the results at each location will have varying results, with an average pH of 8.5 and a standard deviation of 0.22. If the pH level of the reservoir is ok, what is the probability that the sample average is MORE than 8.47?A.-0.833 B.0.2033 C.0.7967 D.-0.14 E.0.4443 F.0.5557
Chemistry
1 answer:
Bumek [7]3 years ago
7 0

Answer:

C.) 0.7967

Explanation:

Hello,

Normal distribution is used here as:

z=\frac{pH_{sample}-pH_{av}}{stand_{dev}*\sqrt{n} }

In this case, the sample's pH is 8.47, the average pH 8.5, standard deviation 0.22 and sample size 37, thus:

z= \frac{8.47-8.5}{0.22/\sqrt{37} }\\z=-0.8295

Now, based on the table for standard normal distribution which comes from a symmetric bell-like graph, the probability is 0.797 which matched with the C answer.

Best regards.

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FromTheMoon [43]

Answer: The correct option is ALL OF THE ABOVE.

Explanation:

TITRATION is a type of volumetric analysis which is used for determining the concentration of solutions. In this process a specific volume of a solution is placed in a conical flask by means of a pipette and small quantities of a second solution is slowly added from a burette until the end point is reached. This is determined by a means of an indicator which shows a characteristic colour change.

During titration, the following precautions should be followed to avoid errors and maintain standardisation in the experiment.

--> Any air bubble in the burette and pipette must be removed during measurement

--> the burette tap should be tightened to avoid leakage.

--> Remove the funnel from the burette before taking any reading to avoid errors in reading the volume.

--> use the base solution such as Sodium Hydroxide Solution to rinse the burette after washing with soap and tap water:

• to remove any air bubble and fill it's tip

• to remove any residual liquid from the water and soap solution which may interfere with the results of the experiment.

• to check if the burette is in good condition.

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3 0
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Convert 5.4g of NaCl to moles
sammy [17]

Answer:

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Explanation:

So you know you have 5.4 g of NaCl and you need to know how many moles there are in this amount of NaCl

  1. You'll need to find the atomic mass of the compound NaCl to help you solve for moles
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Add these two together----> 22.99 + 35.45 = 58.44

Now you can calculate for moles

<u>Written-out method:</u>

<u>5.4 grams of NaCl  |   1 mole of  NaCl              </u>

                                | 58.44 grams NaCl                = .0924 moles of NaCl

<u>Plug into calculator method:</u>

(5.4 g of NaCl/ 58.44g NaCl= .0925 moles)

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