Question

In order to determine moisture content by oven drying method, the sample is kept in the oven fixed at a temperature of:

• A. 105 \(^{\circ}\)F
• B. 120 \(^{\circ}\)F
• C. 105 \(^{\circ}\)C
• D. 140 \(^{\circ}\)C

Hint:

Always pay attention to units. Options are given in both Fahrenheit and Celsius. 105\(^{\circ}\)C is the standard. Temperatures much higher than 110\(^{\circ}\)C can burn off organic matter, while temperatures below 100\(^{\circ}\)C will not effectively remove all the water.

Answer 1

The Correct Option is C

Step 1: Define the objective of oven drying. The aim is to eliminate water from soil pores through evaporation, ensuring the soil's chemical integrity, specifically preventing the combustion of organic matter.
Step 2: Specify the appropriate temperature parameters. Soil samples are typically dried within a temperature range of 105\(^{\circ}\)C to 110\(^{\circ}\)C. This range effectively surpasses water's boiling point (100\(^{\circ}\)C) for complete evaporation, while remaining below the threshold where soil organic matter would char or decompose, thus compromising the accuracy of the dry soil mass measurement.