CHAP 1- INTRODUCTION TO ANALYTICAL CHEMISTRY AND INTRUMENTATION

Which of the following is a characteristic of qualitative analysis?

• Determining the concentration of a substance

• Identifying the presence of a specific component

• Calculating the molar mass of a compound

• Measuring the weight of a sample

Which type of error can be reduced by calibrating instruments?

• Random error

• Systematic error

• Gross error

• Personal error

Which of the following scenarios is an example of replicate samples?

• Comparing sugar content in water samples collected from three locations.

• Measuring the sugar content of water samples from three different rivers.

• Measuring the sugar content of the same water sample three times.

• Collecting one water sample from a river and analyzing it once.

What is the primary purpose of using replicate samples in an experiment?

• To compare differences between groups

• To improve the precision of measurements and reduce random errors.

• To analyze variations across different populations

• To test the effectiveness of a treatment across conditions.

A thermometer consistently measures the temperature of boiling water as 98°C instead of the true value of 100°C. Which statement is correct?

• The thermometer is accurate but not precise.

• The thermometer is precise but not accurate.

• The thermometer is both accurate and precise.

• The thermometer is neither accurate nor precise.

An analytical balance gives the following weight measurements for a 5.00 g standard weight: 4.98 g, 4.97 g, 4.98 g, and 4.99 g. Which of the following statements is true?

• The measurements are high accuracy but low precision.

• The measurements are high precision but low accuracy.

• The measurements are low accuracy, low precision.

• The measurements are high accuracy and high precision.

Which of the following is NOT a source of random error?

• Variations in environmental conditions during an experiment.

• Inconsistent reaction times of an operator.

• A calibration error in an instrument.

• Electrical noise in a measuring device.

How can random errors be minimized in an experiment?

• By repeating the measurements multiple times and taking an average.

• By using a highly sensitive instrument without calibration.

• By correcting for known biases in the measurement system.

• By using the same operator for all measurements.

Which of the following best describes a human error in an experiment?

• Using a faulty thermometer for temperature measurement.

• Reading a measuring scale incorrectly due to poor alignment of the eyes.

• A chemical reaction not proceeding as expected due to contamination.

• Random fluctuations in data caused by external factors.

Which of the following could be classified as an environmental error?

• A thermometer used for measurement is not calibrated properly.

• The temperature of the room changes during an experiment.

• A researcher records a value incorrectly in the lab notebook.

• Electrical interference in a digital balance.