Which of the following does NOT indicate a chemical reaction occurred? A. A gas being produced B. A solid being formed when mixing two liquids C. a sudden unexpected chnage in temperature D. A solid melting into a liquid

In a popular classroom demonstration, solid sodium is added to liquid water and reacts to produce hydrogen gas and aqueous sodium hydroxide. part a write a balanced chemical equation for this reaction. express your answer as a chemical equation. identify all of the phases in your answer.

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.

Which of these is a density dependent factor? a. epidemic b. earthquake c. drought d. hurricane