Calorimetery Problem. It's not a homework but I can't get the answer.

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In summary, a problem involving the combustion of ethanol in a flame calorimeter was discussed. A total of 0.510 g of ethanol was burned in the calorimeter, resulting in the warming of 1200 g of water from 22.46 C to 25.52 C. The heat capacity of the calorimeter was given as 10.4 kJ/C. The change in enthalpy for the combustion of ethanol was calculated using the equation Q(rxn) = Q(water) + Q(calorimeter) and was found to be 47.22 kJ. Additionally, the heat released when 73.5 g of ethanol undergoes combustion was also requested. Further equations involving enthalpy and energy were
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Owelode
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Calorimetery Problem. :( It's not a homework but I can't get the answer.

0.510 g of ethanol is burned in a flame calorimeter (constant pressure) containing 1200 g of water. The water is initially 22.46 C and is warmed up to 25.52 C as a result of the reaction. The heat capacity of the calorimeter is 10.4 kJ/ C. What is the change in enthaply for the combustion of ethanol? Also, calculate the heat released when 73.5 g of ethanol undergoes combustion.
 
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Show an attempt at a solution? Relevant equations? Anything?
 
  • #3


I did attempt it on my own. I was hoping someone would explain it to me though.


I used Q(rxn) = Q(water) + Q(calorimeter)

Also expanded: Q (rxn) = -[(m*s*change in temp.) + (C*change in temp.)]
= -[(1200*4.184*3.06) + (10400*3.06)] <---- I changed things from joules to kJ

And then I am lost from there. I got 47.22 KJ
 
  • #4


Seems to me so far you are doing fine. 47.22kJ per how much ethanol? It will be better to list it either per gram or - even better - per mole. And watch the sign.

--
 
  • #5


Your solution looks good so far, you're almost there. What equations do you know that include enthalpy and energy?
 

FAQ: Calorimetery Problem. It's not a homework but I can't get the answer.

What is calorimetry and why is it important in science?

Calorimetry is the measurement of the amount of heat released or absorbed during a chemical or physical process. It is important in science because it allows us to determine the energy changes in a system, which can help us understand and predict the behavior of substances.

How do you solve a calorimetry problem?

To solve a calorimetry problem, you will need to use the equation Q = m x c x ΔT, where Q is the heat energy, m is the mass of the substance, c is the specific heat capacity of the substance, and ΔT is the change in temperature. You will also need to use the principle of conservation of energy, where the heat lost by one substance is equal to the heat gained by another.

What information do you need to solve a calorimetry problem?

You will need to know the mass, specific heat capacity, and initial and final temperatures of the substances involved in the reaction. You may also need to know the heat of fusion or vaporization for a substance, if it undergoes a phase change during the reaction.

Can calorimetry be used to determine the energy content of food?

Yes, calorimetry can be used to determine the energy content of food. By burning a sample of food in a calorimeter and measuring the heat released, we can calculate the number of calories in the food.

What are some common sources of error in calorimetry experiments?

Some common sources of error in calorimetry experiments include heat loss to the surroundings, incomplete combustion of the substance, and not accounting for the heat of fusion or vaporization of a substance. It is important to carefully control and measure all variables in order to minimize these errors.

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