In 1912, chemist fritz haber developed a process that combined nitrogen from the air with hydrogen at high temperatures and pressures to make ammonia. specifically, the process involved combining one molecule of nitrogen gas (n2) with three molecules of hydrogen gas (h2) to get two molecules of ammonia (nh3). if you write this process in a symbol format, it looks like this: n2 3h2 → 2nh3explain whether this is a chemical or physical change, and why. does it involve elements, compounds, mixtures, or pure substances? also describe how many atoms are involved before and after. what do you notice about the number of atoms?

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.

It takes 945.kj/mol to break a nitrogen-nitrogen triple bond. calculate the maximum wavelength of light for which a nitrogen-nitrogen triple bond could be broken by absorbing a single photon.

The human eye contains a molecule called 11-cis-retinal that changes shape when struck with light of sufficient energy. the change in shape triggers a series of events that results in an electrical signal being sent to the brain that results in vision. the minimum energy required to change the conformation of 11-cis-retinal within the eye is about 164 kj/mol.