2 H2(g) + O2 (g) -> 2 H2O(g) if you have 4.5 g of H2 and 2.1 moles of O2, what is the limiting reagent

How many grams of leftover reagents, if any?

How much volume would the product take up at STP?

Cr(oh)3 -> cr(3+) + 3oh-

Adozen is 1221/12 = 1.751.75 x 12 = 21therefore, 1.75 is the answer.

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.