Why does heat applied to a substance change its temperature or make it change its phase?
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Heat is just a form of energy.\n\nTemperature is the measure of the Average Kinetic energy of a substance.\n\nWhen you add heat energy to something, its moleculues gain kinetic energy is move around faster, thus increasing its temperature.\nWhen a substance changes phases (going from Solid to liquid for example), intermolecular forces must be over come, this requires energy...all the while, the temperature remains constant.
572865
The temperature of any material is a measure of the average kinetic energy of all the atoms in the material. As you increase this kinetic energy (temperature) then the atoms are more energetic the atoms vibrate with more energy this means each atom takes up more space and so the total volume of the material increases aswell
1021038
The definition of the heat of a substance is based on the average kinetic energy of it's particles.\n\nEssentialy, heat *is* average kinetic energy.
718884
&#92;\n..&#92;\n..-----&#92;\n........&#92;\n.........&#92;\n(ignore the periods)\nx axis: time\nY axis: temperature\nThe step is there because the nature of cooling objects. As the naphthalene is cooled, its temp first decreases normally. However, when it begins to solidify, the heat being removed is used up as naphthalene molecules are subjected to intermolecular forces and begin to become a solid. Therefore, the horzontal part is where the substance becomes a solid. Finally, when the naphthalene is fully a solid, the temperature decreases again. An easy way to picture this concept is with boiling water. As some water molecules change to the gaseous state, the temperature of the water does not rise above its boiling point. This is equivilent to the horzontal part of the naphthalene cooling curve. As the substance changes states, energy is being generated/used up, and the temperature does not change for a time. When the conversiion is fully made, the temperature continus on its original course.
625198
Do you know what "specific heat" means? It is the amount of heat required to raise the temperature of a certain amount of substance by 1 degree Celsius.\n\nWater has a very high specific heat compared to most other substances. That means it takes of lot of heat to change the temperature of water. If you ever tried to boil a big pot full of water, you know what I mean.
742562
The melting point is the same as the freezing point, usually. The freezing/melting point is usually lowered to a lower temperature by impurities due to the impurities "messing up" the crystal lattice of the solid phase. The crystal lattice cannot form as easily with a lot of garbage present, so it requires a lower temperature to accomplish freezing. Likewise, the polluted crystal lattice will melt easier and thus it will melt at a lower temperature. This is why we put anti-freeze into our car radiators, to keep your engine block from cracking from the freezing of the coolant water during freezing weather. I hope this helps
406343
it's heat absorbed or radiated during a change of a phase at constant temperature/pressure.
827524
Easier compared to one with a higher heat capacity:\n\nH/(m*Cp) = (delta T), where m is the mass of the object, H is the heat that must be added (or removed) to raise (or lower) its temperature, delta T is its change in temperature, and Cp is its heat capacity. From the above formula, you can see that larger values of Cp result in small temp. changes, for the same heat amount.
141723
Temperature is the degree of heat and heat is the transfer of energy from one body to another as a result of a difference in temperature or a change in phase.
1134140
Depends on the thermoconductive properties of a certain material. Copper for example will heat up or cool down very fast.
700100
Many other materials can be in three states. It depends on the temperature!\nNear the 'triple point' the three phases exist together.\n\nTh
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Now, this answer depends on what you mean by Heat.  Strictly speaking Heat (symbol 'Q')is the energy transferred from one part of a substance to another, or from one object to another due to a change in temperature.  To give you an example, if you heat a spoon on a flame and then insert it in a glass of water, the latter will warm up since Heat moves from the hot spoon to the cooler water.  Heat is a measure of energy and so its units are Joules (J).  The amount of Heat energy transferred is calculated by the formula Q=mcdT (mass x specific heat capacity x change in temperature)\n\nNow, if you are still studying basic Physics, you might come across definitions of Heat which state that it is the Energy driving the vibrations and movement of molecules.  In further Physics this will be called "Internal Energy", symbol 'U'.  In fact, the internal energy of a body can either be changed by giving or taking Heat (with a temperature difference) and/or by doing Work (that is why if you rub your hands together they warm up, despite being at the same temperature).\n\nTemperature is a measure of the degree of hotness of an object (not a measure of the amount of Heat in it!).  So, if an object has a temperature of 0 degree Celsius, this means that this object is as "hot" as pure melting ice.  In the same manner, a stone at a temperature of 100*C is as "hot" as steam above boiling water, and so on.  So, temperature is really a comparison.  There is an Absolute Temperature Scale devised by Kelvin in 1848, who found out that the lowest possible temperature is -273*C.  At this temperature all molecular movement is thought to stop and therefore there cannot exist a place colder than a place where there is no Internal Energy, and hence no heat!  Therefore this temperature is called Absolute Zero, and a temperature scale starting from this point, 0 K(elvin) (=-273*C), was set up. (e.g. 10*C = 10 + 273 = 283K).
53624
An alloy is a combination, either in solution or compound, of two or more elements, which has a combination of at least one metal, and where the resultant material has metallic properties. The result is a metallic substance with properties different from those of its components.\n\nIn chemistry, a physical change is when a substance undergoes some form of change that does not change the substance at the molecular level (i.e. a chemical change). Physical changes do not create new substances, as in a chemical change, but result in the same substance in a different form or shape. A physical change in which a substance changes states between solid, liquid and gas is called a phase change. When water is frozen into ice it undergoes a phase change, and thus a physical change, as it is still water but in a different form. Under normal conditions physical changes can generally be considered reversible, however this does not always hold true.\n\nA chemical change is a process in which reactants are changed into one or more different products. A chemical change occurs whenever new compounds are formed or existing compounds decomposed. During this reaction, chemical bonds between atoms are broken and new chemical bonds formed. This results in a rearrangement of the chemical bonds.\n\nCONCLUSION/ ANSWER to you question!\nThus, brass, an alloy of copper and zinc, will still have individual copper and zince molecules, there is no change at the molecular level. No new compound has been formed. \nSo alloy undergoes PHYSICAL CHANGE!
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I don't really understand what your question is.  In the first place, heat always flows from a warmer object to a cooler one.  That maximizes the number of possible arrangements of energy quanta, leading to an increased entropy.
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When a solid is heated, the molecules become active and the bonds between them come looser, this is how a solid becomes a liquid.\nThe warmer the liquid becomes, the molecular bonds become even less connected and the liquid becomes a gas. (evaporation)\n\nWhen a gas is cooled, the molecular bonds change and they become tighter. or closer together causing the gas to turn back into a liquid (condensation).  And as the molecules become tighter still, then the liquid turns back into a solid.\n\nFreezing and melting points change per molecule.
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By changing the presssure or temperature of the liquid as well as time in contact with the liquid.
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The corect answer is 1) - Its molecules speed up.\nmany times the temperature also rises but not always.\nThink of when you heat ice up. At some point the ice turns to water but does not heat up until all the ice is converted.\n\nI hope you are doing your own homework, not using yahoo as a crutch.