A chemist was hired to monitor a particular lake for possible mercury contamination. He

Question

collected several samples from different locations around the lake, including water samples,
Lake Bottom samples, and plant samples. When the chemist returned to the laboratory, the water
samples were the first to be analyzed. The analysis began by removing a number of aliquots. An
aliquot is:
A. A measure of the contamination of the lake water
B. A combined measure of the contamination in the lake
C. A precise liquid sample taken for analysis
D. Something similar to matrix
2. A detector response may be different for analytes with equal concentrations; thus:
A. More samples must be analyzed.
B. A quantitative analysis is impossible.
C. A calibration curve must be constructed.
D. The detector must be checked thoroughly
3. A sample is said to be homogeneous if:
A. It can be separated by chromatography
B. It has a different composition in different parts of the sample.
C. It can be separated into the individual components by filtering the sample.
D. It is the same throughout.
4. Sampling techniques are very important when analyzing large areas or vast amounts of
materials because you cannot analyze everything. When preparing a composite sample, a chemist
will usually:
A. Analyze as much of the bulk sample as possible.
B. Collect several samples at random from pre-planned locations in the bulk sample and analyze
each.
C. Collect representative samples from various areas of the bulk samples and combine them for
analysis.
D. Not be mindful of the sampling procedure.

Answer 1

Here are the correct answers to the questions based on the information provided:

1. An aliquot is:
   C. A precise liquid sample taken for analysis

2. A detector response may be different for analytes with equal concentrations; thus:
   C. A calibration curve must be constructed.

3. A sample is said to be homogeneous if:
   D. It is the same throughout.

4. When preparing a composite sample, a chemist will usually:
   C. Collect representative samples from various areas of the bulk samples and combine them for analysis.