Can the reactants in a chemical reaction be at different temperatures?
953209
Yes . but when the reaction begins, these temperatures will equilibrate\n\nIt is sometimes not possible to react if one compound is solid and the other is liquid
869284
Enzyme controlled reactions are controlled by temperature quite effectivly. As the temperature increases, the rate of reactions increases because the substrate (the substance the enzyme is catalysing(?)) has more energy, allowing it to move faster, and increasing the chances of collisions. This means that more of the enzymes active sites (where the reaction occurs) are in use. However if the temperature is increased to much, it causes bonds within the enzyme to break, causing it's shape to change, known as denaturing. This means that the active site is also altered and so the substrate will no longer fit. This can be permenant or can be reversed depending on the enzyme and the temperature used. To low a temperature removes the energy from the substrate causing very few reactions to occur. \nIn humans the optimum enzyme temperature is about  35 degrees (slightly more I believe). However, immobilised enzymes (enzymes not able to move through the substrate) and other industrially (and some naturally occuring) enzymes can stand temperatures in excess of 100 degrees (examples of these industrially manufactured ones are those in some detergents).
824613
Rate of chemical reactions depend on - temperature, pressure, concentration and the use of catalyst. The rxn constant (generally used in equilibriums) is often calculated to able to see the rate of the reaction. \n\nX + Y <----> 2V + Z\n\neq constant =  ([V^2]x[Z])/[X]x[Z]) \n\nThe higher the constant, the higher the rate. Equilibrium constant only changes if the there's a temperature change. Concentration changes doesn't effect the constant however it effects the rate. Although pressure changes lead to temperature changes, it's assumed that pressure changes don't effect the constant. If the constant is greater than 10^6, rxn will take place at reasonable rate.
314230
yes...if you change the temperature....the density of water for example changes with its temperature....
551973
TO CAUSE THE CHANGE CHEMICAL REACTION
239222
no, reaction times are too slow at that temperature.  (I'm just guessing, but I'm a chemist.  You should be able to look up reaction energies, try Beilstein.)
970108
it will speed up the reaction since the heat rises the temperature.\nit will also decompose a compound to its elements--decomposition reaction.
865969
Yes they react, for example:\n\nCH3COOCH2CH3 + HCOOH  <==> HCOOCH2CH3 + CH3COOH
967417
Well if work is done, it is no longer an adiabatic process.  So your question doesn't really make sense.\n\nIf I remember correctly from thermodynamics the only way to change the temperature in an adiabatic system is to change the pressure.
900859
If the metal not in the compound is higher on the activity series than the metal in the compound then a reaction will occur and the metals will switch spots. If the metal not in the compound isn't higher on the activity series than the metal in the compound then no reaction will take place. You got to be joking if you think I'm going to be doing 20 problems for you. The only way to learn these is to do them on your own. Just so you know in #6 a reaction will not occur.\n\nHere is an activity series:\nhttp://en.wikipedia.org/wiki/Reactivity_series\n\nREACH doesn't know how to do these, don't listen to his answer.
971455
there are various factors which affects rate of reaction. like temperature,pressure and concentration of the reactants involved. and they all have different effects
444111
Rate of reaction depends upon the concentration of reactants. Since, 6M HCl has a greater conc. than 3M HCl, rate of reaction decreases when Mg reacts with 3M HCl
474830
Heat, availability of reactants, # of enzymes, other competing enzymes (if any).  These are a few.  Heat is one of the biggest as enzymes have specific temperatures at which they operate best.  At different temperatures they tend to slow or shut down completely.  Hope this helps.
426622
temperature differences
1138290
Look up stuff like Arrhenius equations. I don't have my phys chem text book to hand.\n\nFor part two, I think it's D, as I'm fairly certain it's not any of the others.
854687
Temperature is a measure of the average kinetic energy in a substance. A catalyst reduces the activation energy required to go through a reaction. Energy is still usually required though. At lower temperature, there is a lower amount of energy so the process is slowed.
276407
It is possible by a process called distillation where the mixture is slowly warmed n the outcoming gases are cooled and collected but I am not sure that it will work out with common laboratory apparatuses.