Specific heat capacity & heat capacity

In summary, the ratio of specific heat capacity to heat capacity cannot be assigned a dimensionless numerical value, and the question is ill posed. The relevant information for solving the problem is the ratio of 'c' to 'mc', which can be represented as c/mc. The distractors in the question, such as Q=mcΔθ and Q=CΔθ, are not necessary for finding the correct answer. Additionally, the correct answer should have units.
  • #1
ellieee
78
6
Homework Statement
what is the numerical value of the ratio ?
Relevant Equations
Q=mcθ
Q=mc
the answer is 1/2 , but when I did the working out, I got 2/1.. so I'm quite confused
 

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  • #2
The ratio has physical dimension. You therefore cannot assign a dimensionless numerical value.
 
  • #3
Orodruin said:
The ratio has physical dimension. You therefore cannot assign a dimensionless numerical value.
then are you able to explain the answer key ?
 
  • #4
ellieee said:
then are you able to explain the answer key ?
The question is ill posed.
 
  • #5
But with regards to how the question (being ill posed) wants you to do things ...

You have taken heat capacity / specific heat capacity instead of specific heat capacity / heat capacity.
 
  • #6
Orodruin said:
But with regards to how the question (being ill posed) wants you to do things ...

You have taken heat capacity / specific heat capacity instead of specific heat capacity / heat capacity.
how ..? isn't specific heat capacity = mcθ and heat capacity = cθ?
 
  • #7
ellieee said:
isn't specific heat capacity = mcθ and heat capacity = cθ?
No.

Specific capacity is ‘c’ (lower case ‘c’).
Heat capacity is ‘C’ (upper case ‘C’)
C = mc
Warning: it's easy to mix up 'c' and 'C'!

That means you are simply being asked to find ##\frac c {mc}##.

Other notes...

The question contains distractors - unnecessary information to test your ability to identify the relevant information.

Q=mcΔθ gives the heat transferred when an object of mass m and specific heat capacity c changes temperature by Δθ. It is not required in this question.

Q = CΔθ gives the heat transferred when an object of heat capacity C changes temperature by Δθ. It is not required in this question.

The correct answer should have units (as already noted by @Orodruin in Post #2).

Edit - typo' corrected.
 
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FAQ: Specific heat capacity & heat capacity

What is specific heat capacity?

Specific heat capacity, also known as specific heat, is the amount of heat required to raise the temperature of one unit of mass of a substance by one degree Celsius or Kelvin.

How is specific heat capacity different from heat capacity?

Specific heat capacity is a measure of the amount of heat required to raise the temperature of a specific amount of a substance, while heat capacity is a measure of the amount of heat required to raise the temperature of an entire object.

What factors affect the specific heat capacity of a substance?

The specific heat capacity of a substance is affected by its chemical composition, molecular structure, and physical state (solid, liquid, or gas).

Why is specific heat capacity important in thermodynamics?

Specific heat capacity is important in thermodynamics because it helps determine the amount of energy needed to change the temperature of a substance, which is crucial in understanding heat transfer and energy conservation.

How is specific heat capacity measured?

Specific heat capacity is typically measured by conducting experiments in which the amount of heat added to a substance and the resulting change in temperature are recorded. The specific heat capacity can then be calculated using the equation Q = mcΔT, where Q is the heat added, m is the mass of the substance, c is the specific heat capacity, and ΔT is the change in temperature.

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