Question

1. when a substance changes in a way that does not change its composition, a ____ change has occurred. slow chemical fast physical 13. choose all that apply. which two statements are advantages of a model? save time and money before making a product only an approximation of a phenomenon are exactly like the thing they represent study things that are very small

Explanation:

1. A physical change is a change in the form or appearance of a substance without changing its chemical composition. For example, melting ice is a physical change as it is still water (H₂O) in a different state. Chemical changes involve a change in composition, forming new substances. The speed of the change (slow or fast) is not relevant to the type of change in terms of composition.
2. Models in science are useful as they can save time and money before making a product by allowing testing and optimization. Also, they can be used to study things that are very small (like atomic - scale models) or very large, or otherwise difficult to study directly. The fact that a model is only an approximation is not an advantage. And models are not exactly like the things they represent, they are simplifications or representations.

Answer:

1. D. physical
2. save time and money before making a product, study things that are very small