Final answer:
Without specific details about the times for the chemistry and recycling presentations, it's not possible to determine the exact times they occur between 10:00 am and 5:00 pm.
Step-by-step explanation:
The question does not provide specific details regarding the exact times for the chemistry or recycling presentations. To assist with scheduling and planning for such events within the timeframe of 10:00 am to 5:00 pm, it's essential to have clear information. For example, the chemistry presentation could be related to topics such as Chemistry in Everyday Life, States of Matter, or Kinetics & Equilibria. Similarly, a recycling presentation might touch on the practicalities of plastics recycling and its importance in sustainability. Teachers and schools often arrange presentations on such topics to help students grasp the real-world applications of scientific concepts. However, without explicit timing details, it's not possible to determine when exactly these presentations occur within the given timeframe.