Iron oxide F E 2 O 3 is formed when iron F E and oxygen (O2) react in the presence of water (H2O) in the air. Why is the formation of rust, iron oxide, considered a chemical change? I WILL MAKE YOU BRAINLIEST A. Rust is a new substance with different properties than oxygen or iron.

B. None of the above.

C. Rust is a mixture of iron and oxygen.

D. Rust has the same chemical formula as oxygen and iron.

How has the scientific community addressed the safety of chemicals? a. chemicals are repeatedly tested, even those that have existed for a long time. b. existing chemicals are tested if they have never been tested before. c. chemicals are tested if they are suspected to have caused a problem. d. only new chemicals are tested.

Astudent is given a sample of a blue copper sulfate hydrate. he weighs the sample in a dry covered porcelain crucible and got a mass of 23.875 g for the crucible, lid, and sample. the mass of the empty crucible and lid was found earlier to be 22.652 g. he then heats the crucible to expel the water of hydration, keeping the crucible at red heat for 10 minutes with the lid slightly ajar. on colling, he finds the mass of crucible, lid, and contents to be 23.403 g. the sample was changed in the process to very light clue anhydrous cuso4. if there are again 100.0 g of hydrate, how many grams of cuso4 are in it? how many moles of cuso4? (hint: molar mass of cuso4 = 159.6 g / mole. what per cent of the hydrate is cuso4? you may convert the mass of cuso4 to moles.)

What are the three major branches of natural science? • earth and space science, life science, physical science •earth and space science, physical science, chemistry •physical science, life science, chemistry •life science, chemistry, physics