What is the required oven temperature and precision for drying the sample?

• A. 110 ± 5 °C and initial sample weight to the nearest 0.1 %
• B. 100 ± 5 °C and initial sample weight to the nearest 0.1 %
• C. 120 ± 5 °C and initial sample weight to the nearest 0.01 %
• D. 95 ± 5 °C and initial sample weight to the nearest 0.5 %

Answer: (A)

The test is about drying a sample to determine its moisture content, which is done by removing water with a controlled oven heat without damaging the sample. Using about 110 °C ensures water is driven off efficiently, while not so hot that it risks volatilizing other components or causing sample degradation. The ±5 °C tolerance recognizes typical lab oven variability, keeping the procedure practical and repeatable across different instruments and conditions.

Weighing the initial sample with precision to the nearest 0.1% of its mass gives enough resolution to detect small changes in weight as moisture is lost. If the initial weight were recorded with coarser precision, the calculated moisture content could be less reliable, especially for samples with low moisture or small mass losses. Drying to a constant mass and comparing to that precisely measured initial mass yields an accurate moisture determination.