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!
yes
They need a source of energy.A Source of Energy
Energy because you need kenetic energy for collisions to take place
Reactions in the body need a certain amount of energy, called activation energy. Most reactions don't take place because this activation energy is too high. The enzyme bonds to the molecule which diminguishes the activation energy, so the reaction can take place. These enzymes de-bond from the new formed molecule afterwards.
This type of reaction is called ENDOTHERMIC REACTION.
the energy used/released in those reactions are used in other ways that the organism needs in order to survive.
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
They need a source of energy.A Source of Energy
All chemical reactions need a certain amount of activation energy to get started.
no
Candle and all Chemical reactions
Energy because you need kenetic energy for collisions to take place
In a chemical reaction, energy is transformed. You also need to remember that energy is never lost or made, it is transformed from one form to another.
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