When the Coppock Curve gets down to a very low level and then turns up, it signals an important long term entry point. Coppock was a money manager who wanted to find the really great long term buy signals, and was not so much interested smaller swings.
It is inserted in the apparatus set-up between the reaction container and the gas collection system. It is packed with a solid water absorbing drying agent e.g. anhydrous calcium chloride (not for ammonia), calcium oxide (not acidic gases like sulphur dioxide, carbon dioxide and chlorine), anhydrous sodium sulphate.
Metal carbonates such as calcium carbonate (chalk) react with acids to produce the gas carbon dioxide. This can be seen in the equation: Metal carbonate + Acid Salt + Water + Carbon dioxide. The carbon dioxide produced can be tested for in the lab using limewater, which reacts with the carbon dioxide gas. When the limewater reacts with carbon dioxide gas it turns from colourless to milky white in colour.