Carbon can react with hydrogen to form several different compounds. Two compounds that contain only carbon and hydrogen are methane and ethylene. Select the statement that is an example of the law of multiple proportions. The mass ratio of carbon to hydrogen in methane is 3 : 1. The mass ratio of carbon to hydrogen in ethylene is 6: 1. Two different samples of methane have the same ratio of carbon to hydrogen. Two different samples of ethylene have the same ratio of carbon to hydrogen. When carbon and hydrogen react to form ethylene, the mass of ethylene formed is equal to the mass of carbon and hydrogen that reacted. When carbon and hydrogen react to form methane, the mass of methane formed is equal to the mass of carbon and hydrogen that reacted.