variant?
variant?
17) coppe sulfate is hydrated, wen it loses water, water can again be added to make it blue. so reversible. C
18) D - Carbon monoxide reduces Iron oxide. (Iron extraction, remember?)
21) D= to be alkaline ph>7, R and S
24) A = the color gets darker down the halogens group, Thus Astatine is either dark brown or black, cant be dark brown, because the row also says its gas. Astatine is solid as its the last in the group of halogens..
34) A - 78.09% nitrogen, 20.95% oxygen,0.038% carbon dioxide,