It can be + or - depending on the value of the entropy (∆S). Recall, that ∆G = ∆H - T∆S and for a spontaneous reaction, ∆G must be negative, so you can see how this will depend on the values and signs of both enthalpy and entropy.
Candle burning is a spontaneous reaction. It is an exothermic reaction that occurs naturally and releases heat and light energy as the wax is being oxidized in the presence of oxygen from the air.
No, the burning of paper is not a spontaneous reaction as it requires an external heat source to initiate the combustion process. Once the paper is exposed to sufficient heat, it undergoes a chemical reaction with oxygen in the air to produce heat and light energy, resulting in the flame and smoke that we observe during combustion.
The reaction of breaking apart ATP and a phosphate to produce heat is an exergonic reaction. It releases energy in the form of heat. This process is spontaneous because it occurs without the need for an input of additional energy.
Burning charcoal is spontaneous, but not at room temperature. To start the combustion energy must be added (in the form of heat). Once the temperature of the charcoal reaches a certain temperature it reacts exothermically and releases heat. This heat of reaction is sufficient to locally heat more charcoal so that it burns continuously.
Five conditions that can cause spontaneous combustion include: presence of a flammable material, sufficient oxygen supply, heat source or ignition point, confinement of heat, and a chemical reaction that leads to self-heating.
Candle burning is a spontaneous reaction. It is an exothermic reaction that occurs naturally and releases heat and light energy as the wax is being oxidized in the presence of oxygen from the air.
For a spontaneous reaction, the overall change in enthalpy should be negative (exothermic). This means that the products have a lower enthalpy than the reactants, releasing energy in the form of heat.
No, the combustion of gasoline is not spontaneous. It requires a spark or heat source to initiate the reaction.
No, the burning of paper is not a spontaneous reaction as it requires an external heat source to initiate the combustion process. Once the paper is exposed to sufficient heat, it undergoes a chemical reaction with oxygen in the air to produce heat and light energy, resulting in the flame and smoke that we observe during combustion.
A reaction is spontaneous when it releases energy and increases the disorder of the system. This is determined by the change in Gibbs free energy (G) being negative. For example, the combustion of gasoline is a spontaneous reaction because it releases energy in the form of heat and increases the disorder of the system.
Spontaneous ...Happens all by itself; typically unpredictableNon-spontaneous...You have to do something to make it happen.
The reaction of breaking apart ATP and a phosphate to produce heat is an exergonic reaction. It releases energy in the form of heat. This process is spontaneous because it occurs without the need for an input of additional energy.
An endothermic reaction takes in heat from its surroundings. One example of a spontaneous endothermic reaction is an ice pack that doesn't have to be kept in the freezer. When the ice pack is struck with your palm the membrane is broken and the salt is dissolved in the water. The equation would be NH4NO3 plus H2O is equal to NH4 plus NH3.
Reactions are described by this equation: GD = HD - TDS where D = delta for change in values. GD < 0 spontaneous HD < 0 exothermic ; HD > 0 endothermic The first equation is Gibbs free energy. When G is negative, the reaction is spontaneous. In contrast, a positive number G is non spontaneous. The interesting thing is that spontaneous reactions can be EITHER exothermic and endothermic. Lets look at this: lets assume HD has a value of 100. This means TDS would have to be bigger than 100 in order to make GD a negative number. An endothermic reaction which has a positive H can still be exothermic. Here's another way to pose your question: Is an exothermic reaction spontaneous? Always. Is an endothermic reaction spontaneous? This can be either.
For the reaction to occur at room temperature, an external energy source must be provided to drive the reaction, and the reaction will absorb heat from the surroundings. The reaction is non-spontaneous because it does not occur naturally without intervention.
Heat of reaction and enthalpy of reaction are the same thing. Enthalpy, or the heat transfer, cannot be measured, however we can measure the CHANGE of enthalpy which is shown by a value of ∆H. This measured in kilojoules per mole of reactant. (KJ/mol)This value may be positive or negative. For endothermic reactions (which absorb heat), the ∆H value is always positive. For exothermic, where heat is released, the value is negative.
A reaction that produces heat