Pls help on test (no old answers OR files) During a combustion reaction, 9.00 grams of oxygen reacted with 3.00 grams of CH4.

What is the amount of the leftover reactant?

0.74 grams of methane
0.89 grams of methane
1.22 grams of oxygen
1.45 grams of oxygen

List four observations that indicate that a chemical reaction may be taking place

Transportation is the largest single source of air pollution in the united states. air pollution can harm the environment and human health. which technology could offer a solution to this problem? mufflers that reduce noise motors that run on electricity tires that improve gas mileage

8) a mixture of he, ne and ar has a pressure of 7.85 atm. if the ne has a mole fraction of 0.47 and 8) ar has a mole fraction of 0.23, what is the pressure of he? a) 4.2 atm b) 3.7 atm c) 5.5 atm d) 2.4 atm e) 1.8 atm