One of the challenges astronauts face is in space travel is the build-up of carbon dioxide in their spacecraft. The average human exhales about
42.0 g of carbon dioxide per hour. One method to remove the excess
carbon dioxide from the air is using solid lithium hydroxide:
CO2(8)
+
2 LiOHs
-
Li2CO3(2)
+
H2O(1)
If a typical cannister of LiOH contains 750.0 g, how many hours will
it last for one person before it has to be replaced?

Dying the folding patterns of protein molecules can microbiologists better understand cellular processes as well as some diseases, such as alzheimer’s, that are caused by proteins that have misfolded. the folding of these complicated molecules can be simulated on computers, but it takes a lot of processor power and time for even expensive supercomputers to do this. a group of researchers at stanford university developed software that can be used to distribute the processing of data to anyone who is willing to donate time on their idle personal computers. as a result, the researchers have been able to achieve protein-folding simulations that are far better than those other computing methods have done. which statement best describes the work of these researchers? the work is not scientific because the data are not processed in one location. the work is not scientific because the simulations are not reproducible. the researchers applied creativity to solve a problem in running an experiment. the researchers used only well-established scientific techniques.

Joseph has hypothesized that sound travels in waves. if he were following the scientific method, what should he do next? a. ask a question. b. test the hypothesis. c. study the results. d. tell other scientists about his hypothesis.

Compare and contrast physical changes with chemical changes.