Ineed hellppp . 1l of gas reacts with 5l of o2 at stp. a) ch4 .b) c2h6.c) c3h8.d) c4h10.

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.

Ageologist determines that a sample of a mineral can't be scratched by a steel nail but can be scratched by a masonry drill bit. based on this information, the sample mineral has to be softer than a. orthoclase. b. fluorite. c. apatite. d. corundum.

Once similarity and one difference between a mixture of elements and a mixture of compounds