water causing exothermic reaction?
141272
All active metals whose activity is more than H react with water under some or the other condition. For eg. Na metal reacts violently with cold water(the colder the better) liberating hydrogen gas which ignites due to the heat produced in the reaction whereas Mg shows a similar reaction with hot water. The energy liberated is due to the Hydration enrgy which gives the respective metal hydroxides. Even dissolution is a slightly exothermic.
346788
Mg(s) + H20(l) -----> MgOH2 + 1/2 H2\n\nThe magnesium reacts with water in a violently exothermic reaction.  It forms a compound of magnesium hydroxide consisting of one Mg(2+) ion and two hydroxyl ions OH(-) and one half mole of H2 gas is evolved, which is where the sparks and flames come from.
570402
Nothing...unless you light a match, then...BOOM!  In the case of Oxygen and Hydrogen, you'll get pure water afterwards...that should put out the fire you just started :)\n(Not really)
784390
Electrolysis of water causes the formation of hydrogen peroxide with the result of rapid redox reactions that would cause gel to run way too fast. Also, while water can conduct electricity, it  heats up when electrified. Depending on the voltage, the water can get hot enough to melt the gel.
89574
The chemical reaction from adding\nsalt lowers the temperature in which water freezes.\n\nThat is why they throw in onto the roads in areas of winter freezing.
412906
To turn liquid water into steam the weak bonds between the molecules have to be broken and the molecules accelerated enough to leave the water surface and become vapour. This requires energy supplied by heating. \n\nNow add salt.\n\nThe salt consists of NaCl crystals. In water these dissolve into Na+ and Cl- ions. These ions will become surrounded by water molecules that are attracted to them, forming large clumps of molecules. To break these bonds requires more energy than in the case where the salt was absent.\n\nWe have to supply this extra energy and the result is boiling at a higher temperature.
975732
Substance: Water\nLatent Heat Melting J/g:  335\nMelting Temp°C: 0\nLatent Heat Boiling J/g:  2272\nBoiling Temp °C: 100 \nHeat of vaporization (kJ/mol): 40.65
462388
A reaction which gives out heat is known as 'exothermic'.\n\nhttp://en.wikipedia.org/wiki/Exothermic\nhttp://en.wikipedia.org/wiki/Exothermic_reaction\n\nA reaction which seems to absorb heat is known as 'Endothermic'\n\nhttp://en.wikipedia.org/wiki/Endothermic\nhttp://en.wikipedia.org/wiki/Endothermic_reaction
22780
Thank you punnet pundit. I was thinking the same thing. \n\nWhen combining Hydrogen and Oxygen one will get water or hydrogen peroxide. Simple enough. But that's not all there is to it. Just mixing the two doesn't cut it. The mixture must first gain enough energy to react. This is called it's Activation Energy. Which is the amount of energy it needs to absorb in order to carry out a chemical reaction. In the case of water the reaction is spontaneous and once started will continue until there is no longer enough reactants to form products. \n\nIn the case of water the reaction is explosive and quite violent. Liquid Oxygen and Liquid Hydrogen are used in space ships, because the reaction is enough to give the rocket a signifigant amount of upward force. The product is steam really because the water is way above 212 degrees F. but if this is condensed onto something below that temperature you get pure water.\n\nHydrogen peroxide slowly over time can break down in light. That's all I really know about it.
372176
Sounds like you've got too much time on your hands to me!  The ions in solution keep the water molecules farther apart from eachother on average than they would be in pure water.  Therefore the hydrogen bonds are weaker and the water will boil at a lower energy level.  At least that's what I'd guess.
131583
i would think that the radiation from the freqs listed above should all cause excite the water molecules in the same way but to differing extents. that's a very good question; i think i'll research it.
1172999
1) exothermic reaction gives off heat\n2) a catalyst speeds up a rxn\n3) chemical reaction\n4) 1  + 4 --> 1 + 1 + 2\n\ncoefficiant of HCl is one
372088
exothermic is the release of heat to the surroundings. endothermic is the absorption of heat from the surroundings.  Your temperature went up...think about it.  Part 2) specific heat of water is 4.18 j/gK, you have 55g substance. and temperature change was 9.7K...do the math.\nPart 3) well you have qH2O...it is the negative of deltaH!!\nPart 4) you have half as much NaOH...Half as much deltaH\nPart 5) divide delta H from part 3 by the number of moles NaOH in 2g NaOH
888554
Strangely enough, the HOT water would freeze first.  There is a chemical explanation for this.
937277
This is a question that can be answered by using the Conservation of Energy Principle.\n\nThe mass (on the rope) loses Potential Energy:  P.E = mgh\n\nThe water is agitated and heats up, so ultimately this is the conversion of Potential Energy into HeatEnergy. (Internal Energy)\n                  Q  =  m.s.(change of temperature)\nwhere s is the specific heat capacity of the water\nEquate the potential Energy cange to the heat energy change and solve the equation for the change in Temperature.
308806
Consider a liquid (water) and its gas (steam).  To convert water to steam, you first have to heat water to 100 C.  At that point additional energy begins to boil the water.  This is the process where water molecules have enough energy to overcome the attractive force between them (called cohesion, in this case, due to the dipolar attraction between waters).\n\nYou are right in that gases are higher energy (could say hotter), but that's because they've taken the energy from whatever heat source was around when they vaporized.\n\nBack to the water example, water on your skin feels cold because it's absorbing heat from your skin and as the water evaporates, that heat is carried away by the vapor phase molecules (which are moving faster than the liquid form).\n\nThe fast-moving particles from your question have a lot of heat stored, that's why steam at 100 C is more likely to burn your skin than water at 100 C.  It has more heat to transfer.\n\nAs for freon, it depends on which freon you're talking about.  Freon 12 (one of the ones phased out because of ozone depletion) melts at -158 C (Merck Index).
621304
If you are dealing with a reaction involving ammonium carbonate in solution, and are then measuring the temperature rise, you need the heat capacity of water, not ammonium carbonate!\n\nPlease post the whole problem if that is not enough to get you started.