When calculating the % weight change in part 1.2 do we need to consider the weight of the tube?

In determining the percentage weight change, the focus is typically on the weight of the sample or substance being analyzed rather than the weight of the container or tube in which it is held. Here’s a detailed breakdown considering the context:

1. Purpose of Weight Change Calculation: The percentage weight change usually assesses how much a substance has lost or gained weight over a period due to various factors (like evaporation, absorption, etc.). Including the weight of the tube can lead to misleading results because you want to measure changes in the sample, not in its containment.

2. How to Calculate % Weight Change:

   • Find the initial weight of the sample (without the tube).
   • After a certain time or condition (like drying or soaking), measure the weight of the sample again (still excluding the tube).
   • Use the formula for % weight change: $\text{Percentage Weight Change} = \left( \frac{\text{Final Weight} - \text{Initial Weight}}{\text{Initial Weight}} \right) \times 100$

3. Conclusion: In summary, when calculating the percentage weight change, you should not consider the weight of the tube. The focus should be solely on the initial and final weights of the sample itself. This method ensures that the percentage change accurately reflects the behavior of the substance in question.