CHEM question.
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oh yeah my bad.Originally posted by LeonKing:energy were taken in to break the bond, energy were given out when bonds were form.
looks like u've figured it out then. dissociation of ion-ion bonds requires more energy than forming ion-dipole bonds in the solution.
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i believe if you find it in the text book, or surf would save your time than waiting ppl to reply the answer... do your homework, lazy guyOriginally posted by LeonKing:What occurs as potassium nitrate is dissolved in a beaker of water, indicating that the process is endothermic?State your explanation too.Thanks
Will the temperature of water Rise or Fall ? -
yeah. u shld have seen his first reply to me when i tried to analyse his question.Originally posted by Zarks:i believe if you find it in the text book, or surf would save your time than waiting ppl to reply the answer... do your homework, lazy guy -
erm.i post cos i wanna know the ans so do reply stupid stuffs pls moron.If i had knew what the textbook says, i wouldnt have posted it here? What a reeeeeeeee-tard.Originally posted by Zarks:i believe if you find it in the text book, or surf would save your time than waiting ppl to reply the answer... do your homework, lazy guy
the textbook says" when anhydrous sodium carbonate is dissolved in water, there is an increase in temperature.The mixture then loses heat to the surroundings as it cools down again.Hence, the solution has less energy than the solid and water at the start. This is an example of exothermic reaction"
I dont really understand what its trying to imply and thus i posted here and next moment guess what?
ppl posted some irrelevant stuffs.C'mon la i just wanna get that question answered with me understanding the concept and some ppl posted stupid stuffs asking me to do and im lazy and check tb or so called "analyse question". If i could surf web and understand what they trying to say would i have to posted it ? Sometimes its about understanding than knowing the answer.C'mon la use your brain to think for a sec or smth man. -
erm.i post cos i wanna know the ans so dont reply stupid stuffs pls moron.If i had knew what the textbook says, i wouldnt have posted it here? What a reeeeeeeee-tard.Originally posted by Zarks:i believe if you find it in the text book, or surf would save your time than waiting ppl to reply the answer... do your homework, lazy guy
the textbook says" when anhydrous sodium carbonate is dissolved in water, there is an increase in temperature.The mixture then loses heat to the surroundings as it cools down again.Hence, the solution has less energy than the solid and water at the start. This is an example of exothermic reaction"
I dont really understand what its trying to imply and thus i posted here and next moment guess what?
ppl posted some irrelevant stuffs.C'mon la i just wanna get that question answered with me understanding the concept and some ppl posted stupid stuffs asking me to do and im lazy and check tb or so called "analyse question". If i could surf web and understand what they trying to say would i have to posted it ? Sometimes its about understanding than knowing the answer.C'mon la use your brain to think for a sec or smth man. -
Originally posted by LeonKing:
Turn to the next page of the textbook, I believe there is the Energy Level diagram.
erm.i post cos i wanna know the ans so do reply stupid stuffs pls moron.If i had knew what the textbook says, i wouldnt have posted it here? What a reeeeeeeee-tard.
the textbook says" when anhydrous sodium carbonate is dissolved in water, there is an increase in temperature.The mixture then loses heat to the surroundings as it cools down again.Hence, the solution has less energy than the solid and water at the start. This is an example of [b]exothermic reaction"
I dont really understand what its trying to imply and thus i posted here and next moment guess what?
ppl posted some irrelevant stuffs.C'mon la i just wanna get that question answered with me understanding the concept and some ppl posted stupid stuffs asking me to do and im lazy and check tb or so called "analyse question". If i could surf web and understand what they trying to say would i have to posted it ? Sometimes its about understanding than knowing the answer.C'mon la use your brain to think for a sec or smth man.[/b]
See the Exothermic diagram. Notice the arrow showing Energy different of the reactant and product. It is a down arrow. Meaning there is a loss of energy, and it's in the form of heat, during the reaction. This explains why there is an increase of temperature at first.
The second sentence which says that product/mixture losses heat to the surrounding as it cools again. This is simple. Just like a cup of hot milo, it'll eventually cool down to room temperature after some time. -
Exothermic reaction = heat is given out to surroundings
This means that the internal energy of the products decreases but the temperature of the product increases if the energy given out is converted to heat.
Outcome: Temperature of product > temperature of reactants
Total internal energy of product < Total internal energy of reactants.
Endothermic reaction = heat taken in from surroundings.
The process reverses.
Outcome: Temperature of product < temperature of reactants
Total internal energy of product > Total internal energy of reactants.
http://en.wikipedia.org/wiki/Internal_energy
Definition of internal energy
Please don't confuse endothermic reactions by associating heat gained as in heat gained by the product so temperature of the product increases.
Heat is actually taken in from the surroundings to increase the internal energy of the product. -
simply put..
eg u have a beaker of water with 3kJ of energy
potassium nitrate dissolve in water -> endothermic, so it takes energy, maybe 1kJ of energy from its immediate surroundings, the water
so now water has 2kJ of energy left so it feels cooler^^ -
Originally posted by LeonKing:
simply put, when you dissolve it in water there will be enthalpy of hydration which releases energy, and if this energy is larger than that of the lattice energy of the compound, then exothermic, else endothermic
erm.i post cos i wanna know the ans so do reply stupid stuffs pls moron.If i had knew what the textbook says, i wouldnt have posted it here? What a reeeeeeeee-tard.
the textbook says" when anhydrous sodium carbonate is dissolved in water, there is an increase in temperature.The mixture then loses heat to the surroundings as it cools down again.Hence, the solution has less energy than the solid and water at the start. This is an example of [b]exothermic reaction"
I dont really understand what its trying to imply and thus i posted here and next moment guess what?
ppl posted some irrelevant stuffs.C'mon la i just wanna get that question answered with me understanding the concept and some ppl posted stupid stuffs asking me to do and im lazy and check tb or so called "analyse question". If i could surf web and understand what they trying to say would i have to posted it ? Sometimes its about understanding than knowing the answer.C'mon la use your brain to think for a sec or smth man.[/b]