Alkanes are saturated hydrocarbon, that is they contain hydrogen and carbon without a double or triple bond between the carbon atoms, e.g. ethane, propane. Group 7a in the periodic table are called halogens e.g chlorine, bromine. Alkanes react with halogens in a reaction called substitution, where halogens replace hydrogen atoms in alkanes.
it's the last one because it's depended on the rock layers
That's cool man, you should study more... wheres the question though?
21 kg x [(3 x 35.45)/(12.01 + 19.00 + (3 x 35.45))] =
21 kg x (106.35/137.36) = 16.3 kg of chlorine
You just multiply the weight of the material by the fraction of chlorine (by weight). The others are done the same way