During an experiment, a student observes the formation of a precipitate. Why does this indicate that a chemical reaction is likely occurring?
A solid forms, and there is a change of color.
A gas forms, and there is a change of color.
A solid forms, and light is emitted.
A gas forms, and light is emitted.

When a septic tank backs up a goes in to clean it out

Which of the following has wavelength longer than the wavelength of viable light? a) x rays b) gamma rays c) radios waves d) ultraviolet waves

Imagine a small synthetic vesicle made from pure phospholipids enclosing an interior lumen containing 1 mm glucose and 1 mm sodium chloride. if the vesicle is placed in pure water, which of the following happens faster? a. na+ diffuses out. b. cl– diffuses out. c. h2o diffuses in. d. glucose diffuses out. e. sodium chloride diffuses out.