Thermochemical can be defined as part of chemistry that
studies chemical reactions or changes the dynamics of the observed thermal /
thermal only. One of applied science in everyday life is a chemical reaction in
our bodies where the production of energy-the energy required or issued for all
of the tasks that we do. The burning of fuels such as oil and coal used for
power generation. The gasoline burned in a car engine will produce power that
causes the car running. If we have a gas stove means we burn methane (the main
component of natural gas) that produce heat for gold m ak. And through a
sequence of reactions called metabolism, the food you eat will produce the
energy we need for the body to function.
Almost all chemical reactions there is always energy is taken or removed. Let's examine this from happening and how do we know the change of energy.
Events thermochemical
Suppose we are going to do the chemical reactions in an enclosed space so no heat can exit or enter into the reaction mixture. Or the reaction is done in such a way that the total energy remains the same. Also suppose that the potential energy of the reaction is lower than the potential energy of the reactants so that the reaction occurs when there is a decrease of potential energy. But this energy can not just disappear because the total energy (kinetic and potential) should remain constant. Therefore, if the potential energy drops, the kinetic energy should rise means potential energy turns into kinetic energy. The addition amount of kinetic energy will cause the price of the average kinetic energy of molekulmolekul up, which we see as a rise in temperature of the reaction mixture. Mixed reaction to heat.
Most chemical reactions are not closed off from the outside world. When the reaction mixture to heat as described below, the heat can flow into the surroundings. Any changes that can release energy to the surroundings is called exothermic change. Note that if there is an exothermic reaction, the temperature of the reaction mixture will rise and the potential energy of chemical substances in question will fall.
Sometimes there are chemical changes occur which increases the potential energy of the substances concerned. If this happens, then the kinetic energy will come down so that the temperature also dropped. If the system is not closed in around him, the heat can flow to the reaction mixture and the amendments are called endothermic change. Note that if there is an endothermic reaction, the temperature of the reaction mixture will decrease and the potential energy of the substances involved in the reaction will rise.
Measurement of Energy in Chemical Reactions
The standard international unit for energy is Joule (J) derived from kinetic energy. One joule = 1 kgm 2 / s 2. Equivalent to the amount of energy that belongs to an object with a mass of 2 kg and a speed of 1 m / sec (when the British unit, object with a mass of 4.4 lb and a speed of 197 ft / min or 2.2 mile / hour).
1 J = 1 kg m 2 / s 2
Almost all chemical reactions there is always energy is taken or removed. Let's examine this from happening and how do we know the change of energy.
Events thermochemical
Suppose we are going to do the chemical reactions in an enclosed space so no heat can exit or enter into the reaction mixture. Or the reaction is done in such a way that the total energy remains the same. Also suppose that the potential energy of the reaction is lower than the potential energy of the reactants so that the reaction occurs when there is a decrease of potential energy. But this energy can not just disappear because the total energy (kinetic and potential) should remain constant. Therefore, if the potential energy drops, the kinetic energy should rise means potential energy turns into kinetic energy. The addition amount of kinetic energy will cause the price of the average kinetic energy of molekulmolekul up, which we see as a rise in temperature of the reaction mixture. Mixed reaction to heat.
Most chemical reactions are not closed off from the outside world. When the reaction mixture to heat as described below, the heat can flow into the surroundings. Any changes that can release energy to the surroundings is called exothermic change. Note that if there is an exothermic reaction, the temperature of the reaction mixture will rise and the potential energy of chemical substances in question will fall.
Sometimes there are chemical changes occur which increases the potential energy of the substances concerned. If this happens, then the kinetic energy will come down so that the temperature also dropped. If the system is not closed in around him, the heat can flow to the reaction mixture and the amendments are called endothermic change. Note that if there is an endothermic reaction, the temperature of the reaction mixture will decrease and the potential energy of the substances involved in the reaction will rise.
Measurement of Energy in Chemical Reactions
The standard international unit for energy is Joule (J) derived from kinetic energy. One joule = 1 kgm 2 / s 2. Equivalent to the amount of energy that belongs to an object with a mass of 2 kg and a speed of 1 m / sec (when the British unit, object with a mass of 4.4 lb and a speed of 197 ft / min or 2.2 mile / hour).
1 J = 1 kg m 2 / s 2
Smaller unit of energy used in physics called the erg that cost = 1 × 10 -7 J. In reference to the energy involved in the reaction between reagents with molecular size usually replaced the larger unit kilojoules (kJ). One kilojoules = 1000 joules (1 kJ = 1000J).
All forms of energy can be converted entirely into heat and when a chemist measure of energy, usually in the form of heat. Method used to express the heat called calorie (cal abbreviation). The definition is derived from the effect of heat on the temperature of the object. At first calorie is defined as the amount of heat needed to raise the temperature of 1 gram of water with a temperature of 15 0 C for origin 1 0 C. Kilocalorie (kcal) is a unit of kilojoules as well as more appropriate to express energy changes in chemical reactions. Kilocalories units are also used to express the energy contained in the food.
Upon the acceptance of SI, now joules (or kilojoules) and preferably calories redefined in SI units. Now calories and kilocalories exact defined as follows:
1 cal = 4.184 J
1 kcal = 4.184 kJ
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