Some reactions are called endothermic ("into-energy") meaning that they require excess energy in order to react. This will cause the reaction to feel cold. Other rections are exothermic ("out-energy"), meaning that they give off heat.
Reactions only occur when the environment around them contains enough energy (e.g. lighting a fire, cooking) to push them over what's called a reaction threshold. This is their "activation energy". It is different for every reaction. Many reactions that we call spontaneous are actually just reactions that have reached that threshold under normal conditions, which is 1 atmosphere of pressure and 75 degrees Fahrenheit. This is also called Standard Temperature and Pressure, or STP. If you lower the temperature or pressure, these reactions might stop or not occur at all. Other reactions occur at very low temperatures and pressures, and others occur at much higher ones. Every reaction has a temperature-pressure curve which shows under which conditions the reaction will occur.
Lastly, there is an effect called catalysis. This uses a material, often a metal, to artifically lower the reaction energy for the components. This happens by bringing the reactants together on the surface of the metal, where they naturally combine. Using catalysis means having to put less energy into a system for the reaction to occur. Catalysts are reusable and do not become part of the products. A good example of catalytics occurs in your own body: enzymes are special strings of proteins which catalyze certain reactions, such as breaking down food or transferring nutrients into and waste out of cells. In some cases, enzymes cause reactions in your body which would otherwise go so slowly that there's no way you could stay alive!
Not all chemical reactions need energy to start them. Some reactions occur spontaneously, releasing energy as they proceed. These reactions are known as exothermic reactions.
yes
Chemical reactions that absorb energy need an input of energy in the form of heat, light, or electricity to overcome the activation energy barrier and initiate the reaction. This added energy allows the reactant molecules to surpass their energy threshold and transition into a higher-energy state, leading to the formation of products.
This type of reaction is called ENDOTHERMIC REACTION.
Chemical reactions that release energy often occur spontaneously because they lead to a decrease in the overall energy of the system. Exothermic reactions, which release heat energy, are usually spontaneous because they increase the randomness or entropy of the system, following the second law of thermodynamics. This decrease in energy and increase in entropy drive the reaction to proceed without the need for external energy input.
Enzymes speed up chemical reactions in the body by lowering the activation energy needed for the reactions to occur. They do this by bringing substrates together in a precise orientation, reducing the energy required for the reaction to proceed. Enzymes themselves remain unchanged after the reaction and can be reused for multiple reactions.
Chemical reactions are based on the interactions between atoms and molecules, specifically the rearrangement of chemical bonds. These interactions involve breaking existing bonds and forming new ones, resulting in the transformation of reactants into products with different chemical properties.
all they need is energy
yes they all need more or less start up energy
Endothermic reactions need heat.
Candle and all Chemical reactions
no
All chemical reactions need a certain amount of activation energy to get started.
no
Candle and all Chemical reactions
Chemical reactions are based on the interactions between atoms and molecules, specifically the rearrangement of chemical bonds. These interactions involve breaking existing bonds and forming new ones, resulting in the transformation of reactants into products with different chemical properties.
Chemical reactions that absorb energy need an input of energy in the form of heat, light, or electricity to overcome the activation energy barrier and initiate the reaction. This added energy allows the reactant molecules to surpass their energy threshold and transition into a higher-energy state, leading to the formation of products.
Light dependent reactions are reactions the capture light energy and convert it into chemical energy(ATP). It occur in the chloroplast of plant cells Light independent reactions are reactions capture energy and use it to produce food . It does not need sunlight
A chemical reaction need an activation energy to start.