Final answer:
Assumption D (the gas is insoluble in the collecting liquid) and Assumption A (the temperature remains constant) are typically valid assumptions made when using a gas collection apparatus. However, Assumptions B (constant pressure) and C (negligible volume) may not always hold true and adjustments might be needed to account for real-life changes in pressure.
Step-by-step explanation:
When using a gas collection apparatus in a lab, we often assume certain conditions to simplify calculations and understand the behavior of gases. Assumption D: The gas is insoluble in the collecting liquid, is a typical assumption because it simplifies the collection process by ensuring that the gas measured is not lost to dissolving in the liquid and can be counted towards the total collected volume. Assumption A: Assuming the temperature remains constant, aligns with Charles's law, which states that if the pressure of a gas is held constant, the volume of a gas is directly proportional to its absolute temperature, indicating constant temperature facilitates accurate volume measurements. Although Assumption B, that the pressure is constant, might often be considered, real-life scenarios could involve changes in pressure, particularly if the gas is not collected at constant atmospheric pressure or if there are changes in vapor pressure from the collecting liquid. Therefore, adjustments might have to be made using Dalton's Law to account for partial pressure differences. Lastly, Assumption C, the volume of the gas is negligible, is typically not a valid assumption as the entire purpose of the gas collection is to measure its volume accurately.