Unlike the combustion of organic, carbon-based matter such as wood, many explosives and pyrotechnic agents can be combusted underwater, within air-tight containers and in other hypoxic environments. Which of the following explains how a combustion reaction can occur in a hypoxic environment?A.The reaction occurs under adiabatic conditions and is not affected by lack of oxygen.B.Explosions are endothermic reactions that contain all the energy required to initialize combustion.C.The rapid rate at which an explosion occurs overcomes the need for atmospheric oxygen.D.Pyrotechnic agents contain their own oxidizer, so atmospheric oxygen is not required.

Combustion occurs when an oxidation-reduction reaction takes place between a reduced fuel source and an oxidizer, most frequently oxygen.  The reaction between hydrogen and oxygen forms water (Reaction 1) and is highly exothermic and thermodynamically favorable.  At the completion of hydrogen combustion, essentially all H2 molecules have been converted to water.  Nevertheless, at room temperature and atmospheric pressure, molecular hydrogen and oxygen can coexist quite stably.2 H2(g) + O2(g) → 2 H2O(g)Reaction 1A group of researchers designed two prototype internal combustion engines, each of which could inject a hydrogen/oxygen mixture into a 5-mL combustion chamber at a total pressure of 1 atm and could repeat this process for several cycles.  In one engine design, a spark was generated to initiate combustion as hydrogen and oxygen were injected.  In another method, the combustion chamber was coated with a small amount of platinum powder.  Platinum dramatically increases the reaction rate at room temperature without the need for a spark.  The platinum itself is not altered by the reaction and can be reused.  Researchers measured the maximum power output of both engine designs under identical injection and temperature conditions (Figure 1).Figure 1  Relative power outputs of hydrogen engines with different ignition sources at 298 KThe power output of an engine is directly related to the rate of combustion.  In the presence of platinum, researchers measured the engine's rate of water production at various temperatures and H2/O2 mixture compositions.  The results are shown in Figure 2.Figure 2  Rate of combustion in platinum-coated engines under various conditionsAdapted from Schultze, M., Mantzaras, J. (2013) Hetero-/homogeneous combustion of hydrogen/air mixtures over platinum: Fuel-lean versus fuel-rich combustion modes. International Journal of Hydrogen Energy, Vol. 38, Issue 25, 10654-10670. Question 11Platinum most likely increases the reaction rate by stabilizing:A.the reactants.B.the products.C.the intermediate step.D.the transition state.

Which of the following best describes a combustion reaction?a) A reaction where a compound breaks down into simpler substances in the presence of heatb) A reaction where oxygen is added to a compoundc) A reaction where a compound loses oxygen atomsd) A reaction where a compound gains oxygen atoms

Subject: ScienceScenario : Ajay was watching television and saw the news about recurring fire accidents in coal mines.  He searched about the cause of these fire accidents. He found out that this happens due to the spontaneous combustion of coal dust in the mines, as coal dust unexpectedly bursts into flame without requiring any external ignition.He researched more about combustion and found out that it is a chemical process in which a substance reacts with oxygen to give off heat. The combustion process is of three types, as follows. Rapid Combustion Spontaneous combustion Explosive CombustionSubstance burns rapidly. Substance unexpectedly bursts into flame. Substance burns with sudden production of heat, light and sound.It releases a large amount of heat on burning. It releases a small amount of heat on burning. It releases a large amount of heat on burning.It requires an external ignition. No external ignition is required. It requires an external ignition.Example: the combustion of LPG Example: combustion of sodium on exposure to air Example: burning of firecrackers.Question:5 )  Ajay switches on the stove and brings a burning matchstick closer to the stove. Will the burning matchstick light up the stove?A)   Yes, the burning matchstick will light up the stove as the gas burns rapidly on external ignition.B)    No, the burning matchstick will not light up the stove, as the gas does not require any external ignition to burn.C)    No, the burning matchstick will not light up the stove as the gas is not getting any external heat from the matchstick.D)    Yes, the burning matchstick will not light up the stove as the gas burns spontaneously on coming out of the inlets of the stove.NEXT

What is Combustion Reaction?

timeline of the development of the oxygen theory of combustion.