Question

1. choose the best answer. which scientist uses models to invent products like plastics and vaccines? chemist chemical engineer geologist biologist 9) choose the best answer. why are molecular models likely used before creating plastic bottles? to determine the number of hydrogen atoms in polyethylene to identify what polyethylene reacts with to understand how polyethylene behaves when shaped to describe the properties of polyethylene

Explanation:

For question 8:

• A chemist focuses on the composition, structure, properties, and reactions of matter. They use models to understand chemical substances and reactions which can lead to inventing products like plastics (which involve chemical synthesis of polymers) and vaccines (which involve chemical and biochemical processes).
• A chemical engineer is more about the design and operation of chemical plants and large - scale manufacturing processes rather than the initial invention using models in the context of these products.
• A geologist studies the Earth's materials and processes.
• A biologist studies living organisms.

For question 9:

• Molecular models are used to visualize and understand how a molecule (in this case, polyethylene which is used to make plastic bottles) behaves. When creating plastic bottles, understanding how polyethylene behaves when shaped (e.g., how it flows, its flexibility during the manufacturing process) is crucial.
• Determining the number of hydrogen atoms is a basic chemical formula aspect and not the main reason for using models before creating bottles.
• Identifying reactions is more relevant in a chemical synthesis context rather than the shaping of bottles.
• Describing properties is a part of it, but understanding the behavior during the shaping process (which is a dynamic aspect) is more specific to the manufacturing of plastic bottles.

Answer:

1. chemist
2. to understand how polyethylene behaves when shaped