20 10 Fuzhou was rated as "livable city". Fuzhou vigorously promotes energy conservation and emission reduction, environmental protection and ecological construction, and makes it "owned" with practic

20 10 Fuzhou was rated as "livable city". Fuzhou vigorously promotes energy conservation and emission reduction, environmental protection and ecological construction, and makes it "owned" with practical measures. (1) The main component of natural gas is methane, which generates carbon dioxide and water after combustion. The chemical equation is CH4+2O2? Light it? . ? Carbon dioxide +2H2O.

(2)① The boiling points of propane and butane are -42. 1℃ and -0.5℃ respectively, so they are gaseous at normal temperature and pressure. Because propane and butane can react with oxygen to produce carbon dioxide and water, their chemical properties are flammable.

② The chemical formulas CH4, C3H8 and C4H 10 of methane, propane and butane can be converted into C 12H48, C 12H32 and C 12H30. With the same number of carbon atoms, the mass fraction of hydrogen with the most hydrogen atoms will be larger, so methane is the cleanest fuel and has the least impact on the environment.

(3) impure combustible gas will explode when exposed to an open flame.

(3) A. Advocating energy conservation, using clean energy and reducing the emission of greenhouse gas carbon dioxide is in line with the theme;

B. Take a bus or ride a bike to reduce the frequency of using private cars, which is in line with the theme;

C. Turn off the light switch after class and tighten the faucet after washing your hands, which is in line with the theme;

D shopping with a cloth bag, reducing the use of plastic bags, in line with the theme;

So the answer is:

(1) methane; CH4+2O2？ Light it? . ? Carbon dioxide +2H2O. ?

(2)① Qi; Combustible (other reasonable answers are acceptable); ② methane; ③ Explosion (other reasonable answers are acceptable).

(3)ABCD。