An open flask sitting in a lab fridge looks empty, but we know that actually it is filled with a mixture of gases called air. if the flask volume is 1.50 l, and the air is at standard temperature and pressure, how many gaseous molecules does the flask contain?

Which statement describes evidence of a chemical reaction? a) ice melting eliminate b) water boiling c) lighting a match d) grape juice freezing

50 pts plz what is the physical state of matter of baking soda.

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.