Final answer:
When a gas is exposed to a small flame, the outcome depends on the type of gas. Oxygen will support combustion and increase the reaction rate, while flammable gases like methane or hydrogen can combust vigorously, producing heat, water, and potentially carbon monoxide or even explosions.
Step-by-step explanation:
When a gas is exposed to a small flame, several outcomes can occur depending on the type of gas and its properties. For instance, if the gas is oxygen, inserting a glowing splint into it can cause the reaction on the splint to increase in rate by a factor of five, causing the splint to burst back into flame. This is used as a chemical test to identify oxygen because pure oxygen increases the rate of combustion compared to air, which is roughly 20% oxygen.
In the case of flammable gases like methane (CH4) or hydrogen (H2), exposure to a flame can initiate a combustion reaction. For methane, the reaction with oxygen produces carbon dioxide, water, and heat. Hydrogen reacts with oxygen generating a significant amount of heat and water, which is an exothermic reaction. Flammable gases can form explosive mixtures with air under the right concentrations and can be triggered by heat, spark, or sunlight.
Incomplete combustion of gases like methane can result in the formation of carbon monoxide if there is limited oxygen supply. Such reactions not only signify the energy-producing capabilities of these gases but also highlight potential safety risks, such as explosions or poisoning, that can occur if gases are not handled correctly or if there is an improper supply of oxygen during combustion.