... mixture of various hydrocarbon, principally, methylacetylene and propadiene. Map gas is a mixture of various hydrocarbons, principally, methylacetylene and propadiene. ... (outer cone) also gives off a high heat release, similar to propane and natural gas. The combination of a lower ... time. Mapp gas physical and chemical property:1. Its diameter is 75mm, height 267 mm and gross weight 980g, convenient ...