Based on the densities listed with each material, which material(s) would float on a bath of ethanol whose density is 0.789g/ml? i. distilled water, 1.00g/ml ii. octane, 0.706g/ml iii. polyurethane, 1.20g/ml iv. silicon, 2.33g/ml

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

Which common material is an example of a polymer? (25 pts) a. steel b. plastic c. petroleum d. rubbing alcohol

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation: