When mendeleev organized the elements by their he noticed the properties of elements repeated.

An engineering team designs a new rocket that is faster and lighter than any other model being produced. however, the materials end up being so expensive that no company can afford to buy them. which step of the engineering process should have addressed this problem? a. know the background. b. evaluate the results. c. identify a need. d. do the work.

How many grams of oxygen gas are contained in a 15 l sample at 1.02 atm and 28°c? show your work.

How many moles are in 43.9 l of oxygen