Search & Filtering
Complete the table below.
Type of Test n df Confidence level a t-value
1. one-tailed 12 95%
2. one-tailed 15 95%
3. two-tailed 21 99%
4. two-tailed 23 95%
5. one-tailed 25 90%
6. two-tailed 16 90%
7. one-tailed 9 95%
8. two-tailed 27 99%
9. one-tailed 18 90%
10. two-tailed 20 99%
Any remaining solid impurities are removed by filtration before continuing with the analysis. In a typical total analysis method, the procedure might read
After digesting the sample in a beaker, remove any solid impurities by passing the solution containing the analyte through filter paper, collecting the filtrate in a clean Erlenmeyer flask. Rinse the beaker with several small portions of solvent, passing these rinsings through the filter paper and collecting them in the same Erlenmeyer flask. Finally, rinse the filter paper with several portions of solvent, collecting the rinsings in the same Erlenmeyer flask.
For a typical concentration method, however, the procedure might state
After digesting the sample in a beaker, remove any solid impurities by filtering a portion of the solution containing the analyte. Collect and discard the first several mL of filtrate before collecting a sample of approximately 5 mL for further analysis.
Explain why these two procedures are different.
A method for the analysis of Ca2+ in water suffers from an interference in the presence of Zn2+. When the concentration of a Ca2+ is 50 times greater than that Zn2+, an analysis for Ca2+ gives a relative error of 2.0%. What is the value of the selectivity coefficient for this method?
A sample is analyzed to determine the concentration of an analyte. Under the conditions of the analysis the sensitivity is 17.2 ppm-1. What is the analyte’s concentration if S total is 35.2 and S reag is 0.6?
A certain concentration works best when the analyte’s concentration is approximately 10ppb.
a. If the method requires sample of 0.5mL, about what mass of analyte is being measured?
c. Repeat for the case where the analyte is present at 10% w/w. 59
d. Based on your answer to parts (a) - (c) comment on the method’s suitability for the determination of a major analyte.
Use the Laplace transform to solve the given initial-value problem.
y′ + 2y = sin 4t, y(0) = 1
Suppose that the average number of cars abandoned weekly on a certain highway is2.2.
Approximate the probability that there will be:
(a) no abandoned cars in the next week;
(b) at least 2 abandoned cars in the next week. . . " .....
(c) State the key assumptions needed to' make your answers in a) and b) reasonable
Fundamental Principle of counting
You want to put your wattpad in bookshelf. In how many ways can the 7 wattpad be arrange in the shelf?
Calculate the number of grams of AgNO3 needed to make 8.35 L of a 2.23 molar solution of AgNO3 ?
manager of a courier service believes that packets delivered at the end of the month are heavier than those delivered early in the month. As an experiment, he weighed a random sample of 20 packets at the beginning of the month. He found that the mean weight was 5.25 kgs with a standard deviation of 1.20 kgs. Ten packets randomly selected at the end of the month had a mean weight of 4.96 kgs and a standard deviation of 1.15 kgs. At the 0.05 significance level, can it be concluded that the packets delivered at the end of the month weigh more?
