When silver coins are found in ancient shipwrecks, they are coated with a black crust. What question could you ask to help you decide whether the silver underwent a chemical change or a physical change?

Asap! ! who wants to me with my assignment : ) (especially with how i’m gonna draw out the example) you have explored some interesting, informative, and amusing examples of models. now it's time to get creative and make your own model. here is the requirement checklist for your model: ✔ model types can include drawings, diagrams, physical models, virtual simulations, or videos. ✔ models must be created by you, not something selected from an online or outside source. ✔ submit a presentation, picture, video, or screenshot of your model. ✔ submit a one-paragraph summary describing the topic you chose, your model, what it represents, how you made it, and the specific science involved. it is important that you are using science terminology and are accurate. now that you know how to create and submit your model, you will need to choose a topic for your model. choose one of the three topics listed below. select each topic for an overview. -conservation of mass -atomic theory -thermal energy

One of the reactions in a blast furnace used to reduce iron is shown above. how many grams of fe2o3 are required to produce 15.5 g of fe if the reaction occurs in the presence of excess co? a.11.1 g b.22.1 g c.30.0 g d.44.2 g

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.