Question

Drinking water maximum allowable content of cations and anions is usually determined by the Environmental Protection Agency (EPA). In one case, the Nitrite (NO??) was measured by two methods in rainwater and unchlorinated drinking water. The results ± standard deviation (number of samples) are shown in the picture below. A) For each method, does the drinking water contain significantly more nitrite than the rainwater (at the 95% confidence level)? B) Do the two methods agree with each other at the 95% confidence level for both rainwater and drinking water? C) Do you think that error reporting in the below image has been done appropriately? Why do you think so? D) IF The maximum allowable level for arsenic (As) is 0.010 ppm for drinking water per EPA regulation. The arsenic concentration for the drinking water of a municipality was measured to be 4.92 * 10?? M arsenic. i) What is the arsenic concentration of the water sample in ppm? ii) Does the water sample meet EPA guidelines? Assume the drinking water sample has a density of 1.0000 g/mL. Molar mass of As = 74.92160 g/mol. Sample source Gas chromatography Spectrophotometry Rainwater 0.069 ± 0.005 mg/L (n = 7) 0.063 ± 0.008 mg/L (n = 5) Drinking water 0.078 ± 0.007 mg/L (n = 5) 0.087 ± 0.008 mg/L (n = 5) SOURCE: I. Sarudi and J. Nagy, Talanta 1995, 42, 1099.

          Drinking water maximum allowable content of cations and anions is usually determined by the Environmental Protection Agency (EPA). In one case, the Nitrite (NO??) was measured by two methods in rainwater and unchlorinated drinking water. The results ± standard deviation (number of samples) are shown in the picture below.

A) For each method, does the drinking water contain significantly more nitrite than the rainwater (at the 95% confidence level)?
B) Do the two methods agree with each other at the 95% confidence level for both rainwater and drinking water?
C) Do you think that error reporting in the below image has been done appropriately? Why do you think so?
D) IF The maximum allowable level for arsenic (As) is 0.010 ppm for drinking water per EPA regulation. The arsenic concentration for the drinking water of a municipality was measured to be 4.92 * 10?? M arsenic.
i) What is the arsenic concentration of the water sample in ppm?
ii) Does the water sample meet EPA guidelines?
Assume the drinking water sample has a density of 1.0000 g/mL. Molar mass of As = 74.92160 g/mol.

Sample source Gas chromatography Spectrophotometry
Rainwater 0.069 ± 0.005 mg/L (n = 7) 0.063 ± 0.008 mg/L (n = 5)
Drinking water 0.078 ± 0.007 mg/L (n = 5) 0.087 ± 0.008 mg/L (n = 5)
SOURCE: I. Sarudi and J. Nagy, Talanta 1995, 42, 1099.

Drinking water maximum allowable content of cations and anions is usually determined by the Environmental Protection Agency (EPA). In one case, the Nitrite (NO??) was measured by two methods in rainwater and unchlorinated drinking water. The results ± standard deviation (number of samples) are shown in the picture below.

A) For each method, does the drinking water contain significantly more nitrite than the rainwater (at the 95% confidence level)?
B) Do the two methods agree with each other at the 95% confidence level for both rainwater and drinking water?
C) Do you think that error reporting in the below image has been done appropriately? Why do you think so?
D) IF The maximum allowable level for arsenic (As) is 0.010 ppm for drinking water per EPA regulation. The arsenic concentration for the drinking water of a municipality was measured to be 4.92 * 10?? M arsenic.
i) What is the arsenic concentration of the water sample in ppm?
ii) Does the water sample meet EPA guidelines?
Assume the drinking water sample has a density of 1.0000 g/mL. Molar mass of As = 74.92160 g/mol.

Sample source Gas chromatography Spectrophotometry
Rainwater 0.069 ± 0.005 mg/L (n = 7) 0.063 ± 0.008 mg/L (n = 5)
Drinking water 0.078 ± 0.007 mg/L (n = 5) 0.087 ± 0.008 mg/L (n = 5)
SOURCE: I. Sarudi and J. Nagy, Talanta 1995, 42, 1099.

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