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what is the difference between molar heat of a solution and the heat capacity?"compare...

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missyanyan | Student | (Level 1) Honors

Posted August 25, 2012 at 1:13 PM via web

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what is the difference between molar heat of a solution and the heat capacity?

"compare your value of the molar heat of solution for your chemical with the published value." (NaNO3)

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llltkl | College Teacher | (Level 3) Valedictorian

Posted August 25, 2012 at 5:24 PM (Answer #1)

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Molar heat of solution is the amount of heat released (or absorbed) when one mole of a particular substance is dissolved in a large volume of a particular solvent. Its value may be both positive and negative meaning heat has been generated or absorbed during dissolution, respectively. NH4Cl, NaNO3, NH4NO3 etc. absorbs heat whereas CaCl2, HCl etc. generates heat when dissolved in water.

The quantity of heat required to raise the temperature of a body by one degree is called its heat capacity. The heat capacity of a gram-mole of a substance is its molar heat capacity. Its value is always positive, meaning one has to apply some heat always, in order to raise its temperature by one (or more) degree.

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cassielargy | Student, Undergraduate | (Level 1) Honors

Posted August 26, 2012 at 3:45 AM (Answer #2)

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Ratio of heat absorbed by a material to the temperature change. It is usually expressed as calories per degree in terms of the actual amount of material being considered, most commonly a mole (the molecular weight in grams). The heat capacity in calories per gram is called specific heat. The definition of the calorie is based on the specific heat of water, defined as one…

Energy is required to raise the temperature of an object. How much energy is required depends on what the object is made of. If we are going to compare how much energy is required to heat an object we must consider we are comparing like-with-like. The specific heat capacity gives us the energy required to raise the temperature of unit mass by one-degree Centigrade.

The word specific in physics has a specific definition, it means a mass of 1kg.

Mathematically, Q=mcΔθ, where m is the mass of the object being heated, c is the specific heat capacity of of the material the object is made from and δθ is temperature difference between the final and initial temperatures in K or °C.



To measure the energy required we use a source of heat, either electrical or chemical. The specific heat capacity is then the energy input = mass x specific heat capacity x the change in temperature.


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