0
Enthalpy is the amount of energy in a system and when this changes (when a reaction happens), the energy is either released (exothermic) or absorbed (endothermic) and this energy is usually released or absorbed as heat. Therefore when the enthalpy decreases, heat is released from the system making it exothermic. In contrast, when the enthalpy increases, heat is absorbed making it endothermic.
Enthalpy of water (100% liquid, 0% steam) has a direct relation with pressure and temperature
Enthalpy of vaporisation (mixture of liquid and steam) has an inverse relation with pressure and temperature
Enthalpy of steam (100% steam, 0% liquid) at saturation has a direct relation with pressure and temperature
Enthalpy of super-heated steam (steam at a temperature above its saturation temperature) has a direct relation with temperature and an inverse relation with pressure
enthalpy is a diffrence of reducing temperature. and temperature is a hotness or coldness of a product or a area.
The above answer can be re-state as:
Enthalpy is a measure of the total energy inside a thermodynamic system. (emphasize on thermodynamic because enthalpy and temperature in classical way are not defined beyond chemical equilibrium). There are actually two types of enthalpy but people don't usually make a difference: formation enthalpy and sensbile enthalpy. Sensible enthalpy is the one related to temperature. Sensible enthalpy is the energy change in the system as the temperature of the system is modified. Mathematically is expressed in terms of specific heat at p=const and temperature i.e.: h=cp*T (for calorically perfect gas only). The formation enthalpy is a different story has to do with the chemical energy of the molecule (sometimes this is also called heat of formation). Hope this helps!
Add your answer:
Earn +20 pts
What is the relationship between temperature and voltage amplification Theory and Mathematical Information?
With higher temperature, low voltage
Why you calculate enthapy?
Generally enthalpy is analgous to the energy of a material at a particular temperature and pressure. It is calculated to determine the energy a material holds, or more often, enthalpy differences are calculated to determine how much energy is required to bring a material from one temperature and pressure to another temperature and pressure.
What is the relationship between resistance and temperature?
• ntc 'negative temperature coefficient': its resistance decreases as the temperature increases• ptc 'positive temperature coefficient': its resistance increases as the temperature increases
Is the heat content of a system at a constant pressure?
Yes it is possible, for example when water freezes there is a point when the temperature remains constant however energy is released as the water condenses.
What is the Relationship between resistance and inductance in a RL circuit?
What is the Relationship between resistance and inductance in a RL circuit?
What is the relationship between enthalpy and temperature in an isothermal process?
In an isothermal process, the temperature remains constant. Therefore, the enthalpy change is directly proportional to the temperature change.
What is the relationship between temperature and enthalpy change for an ideal gas?
The relationship between temperature and enthalpy change for an ideal gas is described by the equation H nCpT, where H is the enthalpy change, n is the number of moles of the gas, Cp is the molar heat capacity at constant pressure, and T is the change in temperature. This equation shows that the enthalpy change is directly proportional to the temperature change for an ideal gas.
What is the relationship between enthalpy and temperature change during an adiabatic expansion process?
During an adiabatic expansion process, there is no heat exchange with the surroundings. As a result, the change in enthalpy is directly related to the change in temperature. When a gas expands adiabatically, its temperature decreases, leading to a decrease in enthalpy.
What is the relationship between Gibbs free energy and enthalpy in a chemical reaction?
In a chemical reaction, the relationship between Gibbs free energy and enthalpy is described by the equation G H - TS, where G is the change in Gibbs free energy, H is the change in enthalpy, T is the temperature in Kelvin, and S is the change in entropy. This equation shows that the Gibbs free energy change is influenced by both the enthalpy change and the entropy change in a reaction.
What is the relationship between constant pressure enthalpy and the changes in a system's energy content during a process?
Constant pressure enthalpy is a measure of the energy content of a system at a constant pressure. During a process, changes in the system's energy content are reflected in the enthalpy changes. The relationship between constant pressure enthalpy and changes in energy content is that they are directly related - as the enthalpy changes, so does the energy content of the system.
What is the relationship between the standard enthalpy of formation and the standard enthalpy of reaction in chemical reactions?
The standard enthalpy of formation is the energy change when one mole of a compound is formed from its elements in their standard states. The standard enthalpy of reaction is the energy change for a reaction under standard conditions. The relationship between the two is that the standard enthalpy of reaction is the sum of the standard enthalpies of formation of the products minus the sum of the standard enthalpies of formation of the reactants.
Is the enthalpy change (H) independent of temperature?
No, the enthalpy change (H) is not independent of temperature. It can vary with temperature changes.
What is the relationship between the formation reactions that are exothermic and their corresponding enthalpy of formation values (hf)?
The relationship between exothermic formation reactions and their enthalpy of formation values is that exothermic reactions release heat energy when the compound is formed. This results in a negative enthalpy of formation value (hf) because the reaction is giving off energy.
What is the relationship between the enthalpy h and entropy s of a reaction that is spontaneous at higher temperatures but not at lower temperatures?
The relationship between enthalpy (H) and entropy (S) is described by the Gibbs free energy equation, ĪG = ĪH - TĪS, where ĪG is the change in Gibbs free energy, ĪH is the change in enthalpy, T is the temperature in Kelvin, and ĪS is the change in entropy. For a reaction to be spontaneous at higher temperatures but not at lower temperatures, the entropy term (TĪS) must dominate over the enthalpy term (ĪH) in the Gibbs free energy equation. This suggests that the increase in entropy with temperature plays a more significant role in driving the reaction towards spontaneity than the enthalpy change.
How does the enthalpy of an ideal gas vary with temperature?
The enthalpy of an ideal gas increases with temperature. As the temperature rises, the kinetic energy of the gas molecules also increases, leading to higher enthalpy.
What is the relationship between enthalpy, entropy, and free energy in a chemical reaction?
In a chemical reaction, enthalpy, entropy, and free energy are related. Enthalpy is the heat energy exchanged during a reaction, entropy is the measure of disorder or randomness, and free energy is the energy available to do work. The relationship between these three factors is described by the Gibbs free energy equation: G H - TS, where G is the change in free energy, H is the change in enthalpy, S is the change in entropy, and T is the temperature in Kelvin. This equation shows that for a reaction to be spontaneous, the change in free energy must be negative, meaning that the enthalpy change and entropy change must work together in the right direction.
How does gibbs energy relate to the changes in ethalpy and ethropy?
Gibbs energy accounts for both enthalpy (heat) and entropy (disorder) in a system. A reaction will be spontaneous if the Gibbs energy change is negative, which occurs when enthalpy is negative (exothermic) and/or entropy is positive (increased disorder). The relationship between Gibbs energy, enthalpy, and entropy is described by the equation ĪG = ĪH - TĪS, where T is temperature in Kelvin.
