The half-life of element-Z is 30 minutes. If it takes the delivery company 2 hours to deliver then what mass should you order if you need 10.0 grams?

The tilt of the earth's axis of rotation is responsible for the a) ocean's tides. b) size of the moon. c) brightness of stars. d) earth’s seasons.

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.

If a solution had a ph of 7 what is the solution