Which of the following are sources of weighing error? Weighing a sample that is warmer than ambient temperature Cooling a sample in a desiccator prior to weighing Periodically calibrating the balance The temperature of the balance changing over time

Solid-phase extraction is a sample preparation technique. Which statement(s) is/are NOT true for an aqueous solid-phase extraction?

Student’s t is a statistical tool used most frequently to express confidence intervals. compare results from different experiments. evaluate the probability of an experimental value agreeing with a “known” value. determine if a questionable data point should be discarded.

Find the  margin of error for the 95% confidence interval  of the following data: (report 3 decimal places) [A], [B], [C], [D]

Which statements are TRUE regarding the expression of the concentration of a 54.9-ppm Fe solution in terms of molarity?

___________ is a consistent error that can be detected and corrected.

Which of the data set(s) is the most accurate? [A], [B] Which of the data set(s) is the most precise? [B] Which of the data set(s) is the most affected by a systematic error? [C] Which data set(s) is the most affected by random error? [A]

A _____________ is a reagent that protects a component of the analyte from reaction with EDTA.

The Volhard method cannot be employed to analyze

Which step(s) is/are NOT required in the practice of weighing by difference? Weigh a capped bottle containing the dry reagent. Quickly pour some of the dry reagent from the weighing bottle into a receiver. Weigh the receiver containing the dry reagent. Recap the bottle that now contains less of the dry reagent. Reweigh the capped bottle that contains less of the dry reagent.