List four observations that suggest chemical change is occurring

Ineed this asap part i: scientific method what is the difference between science and pseudoscience? what is the scientific method?

Steam reforming of methane ( ch4) produces "synthesis gas," a mixture of carbon monoxide gas and hydrogen gas, which is the starting point for many important industrial chemical syntheses. an industrial chemist studying this reaction fills a 1.5 l flask with 3.5 atm of methane gas and 1.3 atm of water vapor at 43.0°c. he then raises the temperature, and when the mixture has come to equilibrium measures the partial pressure of carbon monoxide gas to be 1 .0 atm. calculate the pressure equilibrium constant for the steam reforming of methane at the final temperature of the mixture. round your answer to 2 significant digits.

Fred is studying a substance that is made out of only one element. this means that