Solving Thermal Physics Problem: Specific Heat Calculation

In summary, the specific heat of a metal is 2.65 J/kg C if 135 kJ of heat is needed to raise it from 20 deg. C to 30 deg. C.
  • #1
metalmagik
131
0
Sounds like Chemistry to me. So our teacher sends us all home with packets full of info on things we've never covered in class and I've got to do this. Here's one problem that I'm not sure if I did right.

What is the specific heat of a metal substance if 135 kJ of heat is needed to raise 5.1 kg of the metal from 20 deg. C to 30 deg. C?

The formula is "heat needed to raise temp" = (mass)(specific heat)(delta temp)

so I made it 135 = (5.1)(x)(10)

and I got 2.65 J/Kgdeg.C for specific heat. Is this correct? Thank you
 
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  • #2
metalmagik said:
Sounds like Chemistry to me. So our teacher sends us all home with packets full of info on things we've never covered in class and I've got to do this. Here's one problem that I'm not sure if I did right.

What is the specific heat of a metal substance if 135 kJ of heat is needed to raise 5.1 kg of the metal from 20 deg. C to 30 deg. C?

The formula is "heat needed to raise temp" = (mass)(specific heat)(delta temp)

so I made it 135 = (5.1)(x)(10)

and I got 2.65 J/Kgdeg.C for specific heat. Is this correct? Thank you
Almost correct. You overlooked one small thing. You need 135 kJ of heat. You either have 2,650 J/(kg C) or 2.65 kJ/(kg C).
 
  • #3
AH much appreciated thank you, if you or anyone else could answer another small question in this same topic i would appreciate it, I have a graph here separated into 5 different parts (A-B, B-C, C-D, D-E, E-F) It is a curve going upwards...I just need to know how to calculate the heat of fusion of the substance using the curve in the graph...I can use the formula and calculate the heat of fusion for each little piece but...do I add them after that? I'm just not really sure...any help is once again appreciated, if you need me to clarify or draw the graph I will, gladly. Thank you.
 

1. What is specific heat and why is it important in thermal physics?

Specific heat is the amount of heat required to raise the temperature of one unit mass of a substance by one degree. In thermal physics, it is important because it helps us understand how different materials respond to changes in temperature and how much energy is needed to heat or cool them.

2. How do you calculate specific heat?

The formula for specific heat is Q = mcΔT, where Q is the amount of heat transferred, m is the mass of the substance, c is the specific heat, and ΔT is the change in temperature. This formula can be rearranged to solve for c: c = Q/(mΔT).

3. What units are used for specific heat?

Specific heat is typically measured in units of J/(kg·K) or J/(kg·°C). However, other units such as cal/(g·K) or cal/(g·°C) may also be used.

4. How does specific heat vary between different substances?

The specific heat of a substance depends on its atomic and molecular structure, as well as its phase (solid, liquid, or gas). Generally, substances with stronger intermolecular forces tend to have higher specific heats, meaning they require more energy to raise their temperature. For example, water has a higher specific heat than iron due to its stronger hydrogen bonds.

5. How can specific heat be experimentally determined?

One common method for determining specific heat experimentally is by using a calorimeter. A known mass of the substance is heated or cooled, and the change in temperature is measured. The amount of heat transferred can then be calculated using the formula Q = mcΔT, and the specific heat can be determined from that value.

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