You use chrome-plated copper pipe tubing when the tubing is above ground and outside a wall. The purpose of the chrome plate is solely aesthetic. Though some structural integrity is added to the copper with the plating of chrome, that's not the chrome's purpose. Take care when connecting chrome-plated copper pipe in order to avoid scratching it or creating a blemish on the chrome. The three methods of connecting chrome-plated copper are the same as those used to connect standard copper tubing, with a few minor variances.
Connect the chrome-plated copper tubes with a push fitting. The O-rings inside a push fitting don't adhere to chrome, so you must first file the chrome from the tube. To do so, measure and record the distance from the edge of the mouth of the fitting to the stopper inside the fitting. The stopper is a plastic buffer with the same circumference as the interior circumference as the tubing, meaning the wall of the tubing cannot slide past it when the tube is pushed into the fitting. From the end of both chrome-plated tubes, measure the distance you recorded and make a mark on the tube. File away all chrome from the end of the tube to the mark, then slide one tube into each end of the fitting.
Slide the compression fitting over the end of one of the tubes and slide the other tube into the opposing end of the fitting. Place a pipe wrench around each end of the fitting. Turn both ends clockwise. This means the two wrenches rotate in opposing directions around the fittings. Tighten the fitting snugly, but not too tight or you'll bend the tubing.
Solder a coupling to the tubes to connect them. As with a push fitting, first you must remove the chrome. For the correct distance to file, measure the length of coupling and divide that number in half. File the tubes. Be careful not to remove the nickel coating between the copper and the chrome. The chrome and nickel are different. Once you reach the nickel layer, stop filing. Slide the coupling over the end of one of the tubes. Solder the coupling to the tube. Slide the other tube into the coupling and solder.