Specific Heat Capacity and Energy

In summary, the conversation is about a confusion regarding the formula for energy needed and how it relates to power and rate of reduction. The student initially believes that the units of the formula do not make sense, but later realizes that the units cancel out and the result is in joules, as expected.
  • #1
Mukilab
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Homework Statement



http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_PC_2006_QP.pdf

Q15b

Answers:
http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_PC_2006_MS.pdf

I am confused on how the answer is reached, specifically how the formula energy needed=power/rate of reduction is laid out

Homework Equations



energy needed = power/rate of reduction

The Attempt at a Solution



What I am confused about is that since power is in J/s and rate of reduction is in kg/s that would make Energy needed into J/kg... or specific heat capacity and not energy itself.

How does this work?
 
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  • #2
Nevermind I realized that since the kg is 1, j/kg gives joules anyway
 

Related to Specific Heat Capacity and Energy

1. What is specific heat capacity and how is it different from heat capacity?

Specific heat capacity is the amount of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius. It is different from heat capacity, which is the amount of heat required to raise the temperature of an entire object by 1 degree Celsius.

2. How is specific heat capacity measured?

Specific heat capacity is measured using a calorimeter, which is a device that measures the amount of heat released or absorbed during a chemical or physical process. The substance's mass, initial and final temperatures, and the amount of heat added or removed are all used in the calculation.

3. What factors affect the specific heat capacity of a substance?

The specific heat capacity of a substance is affected by its molecular structure, density, and phase (solid, liquid, or gas). Substances with stronger bonds between molecules tend to have higher specific heat capacities, while substances with weaker bonds have lower specific heat capacities.

4. How does specific heat capacity relate to energy?

Specific heat capacity is directly related to the amount of energy required to change the temperature of a substance. The higher the specific heat capacity, the more heat energy is needed to raise the temperature of a substance. This is why substances with high specific heat capacities, like water, are often used to store and transfer thermal energy.

5. Can specific heat capacity be changed?

Specific heat capacity is an intrinsic property of a substance and cannot be changed. However, the amount of heat energy required to change the temperature of a substance can be altered by changing the substance's mass or the amount of heat added or removed. Additionally, the specific heat capacity of a substance can vary slightly with temperature, but this change is usually negligible.

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