Select all choices that represent ppm.

The concentration of chromium in blood serum of a control and a diseased group were measured. Which of the following equation would you use to evaluate if the results of the two groups were statistically different or same?

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• None of the choices.

Analysis for a sample was done in triplicate. To compare if the determined concentration is statistically the same or different at the 95% confidence interval, what value of tcrit should be used?

Which of the following equations should you use to determine the standard deviation of the calculated result for this calculation: y = 2.77 (±0.06) × 0.36(±0.004)

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• None of the choices.

A statistical test was applied to test if a method #1 is statistically the same or different compared to method #2. For the following set of data from each method at the 95% confidence interval, what value of tcrit should be used in the statistical test?

Between NaCN (sodium cyanide) and NaF (sodium fluoride), which salt would yield a more basic solution when dissolved in deionized water?

Ka of HCN = 6.2 × 10^-10

Ka of HF = 6.8 × 10^-4

• NaCN

• NaF

What is the pH of an aqueous solution of 0.150 M of NH₄CN (ammonium cyanide)?

Ka of NH₄⁺: 5.7 × 10^-10

Ka of HCN: 6.2 × 10^-10

• pH < 7

• pH ≈ 7

• pH > 7

• pH = 14

• pH cannot be determined.

Which of the following titration curves best represents the titration of 0.1M NaCH₃COO (sodium acetate) with 0.1 M HCl?

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For the titration of 40 mL 0.10 M weak monoprotic acid, HA, with 0.10 M of NaOH (sodium hydroxide), what volume of NaOH should be added to the acid solution to reach the equivalence point? Ka of HA = 1 × 10^-8

• 50 mL

• 20 mL

• 30 mL

• 40 mL

For the titration of 40 mL 0.10 M NaHCOO (sodium formate), with 0.10 M HCl (hydrochloric acid) what is the pH of the solution in the flask at the equivalence point?

Ka of HCOOH = 1.8 × 10^-4

• pH < 7

• pH = 7

• pH > 7

• pH = 14

• pH cannot be determined.