15. This base can be used in fighting certain types of fires because at high temperatures it turns into carbon dioxide, which smothers flames by obstructing the flow of oxygen to the fire. What base is it?

Calcium carbonate (CaCO3)

Explanation:

Calcium carbonate is a solid base. It is known to decompose at high temperature giving out carbon dioxide as follows;

CaCO3(s)> CaO(s) + CO2(g)

The carbon dioxide gas produced is very useful in fire fighting because it smoothers flames.

This reaction only occurs at very high temperature, when a lot of heat has been applied to the system. Hence CaCO3 is a base that can be used in fighting certain kinds of fires.

explanation:

two years ago, when picking flowers in the mountains back of yosemite valley, i found a book. it was blotted and storm-beaten; all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however; many of the inner pages were well preserved. and although all were more or less stained and torn, whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today; its granite pages have been torn and blurred by the same storms that wasted the castaway book.

two years ago, when picking flowers in the mountains back of yosemite valley; i found a book. it was blotted and storm-beaten, all of its outer pages were mealy and crumbly. the paper seemed to dissolve like the snow beneath which it had been buried, however, many of the inner pages were well preserved. and although all were more or less stained and torn; whole chapters were easily readable. this is the condition of the great open book of yosemite glaciers today, its granite pages have been torn and blurred by the same storms that wasted the castaway book.