How Do You Calculate Specific Heat and Identify Unknown Substances?

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SUMMARY

This discussion focuses on calculating specific heat and identifying unknown substances through energy transfer. The first problem involves determining the energy required to raise the temperature of 18 kg of carbon from -5°C to 17°C, using the formula energy = C × m × ΔT, where C is the specific heat capacity. The second problem requires calculating the specific heat capacity of an unknown substance that absorbs 7320 J of energy while its temperature rises from 5°C to 30°C. The correct approach involves rearranging the same formula to solve for C.

PREREQUISITES
  • Understanding of specific heat capacity and its formula
  • Basic knowledge of thermodynamics
  • Ability to perform unit conversions (e.g., kg to g)
  • Familiarity with temperature scales (Celsius)
NEXT STEPS
  • Learn how to calculate specific heat capacity using the formula C = Q / (m × ΔT)
  • Research common specific heat values for various substances
  • Explore thermodynamic principles related to energy transfer
  • Study the impact of mass and temperature change on energy calculations
USEFUL FOR

Students in physics or chemistry, educators teaching thermodynamics, and professionals involved in material science or engineering who need to understand heat transfer and material properties.

lynn0808
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Need help... Dont know how to solve correctly.

a) Determine the amount of energy to raise the temperature of 18kg of carbon from -5celsius to 17celsius.

b) 200g of a certain substance absorbs 7320J of energy and experienced a temperature rise form 5celsius to 30celsius. By calculating its 'C' value, identify as near as possible, the unknown substance.

here's some work I did

delta t= 17-5=12Celsius.
M=18kg
C=709j/kg
energy=cXmXdelta t
709J/kg.K X 18kg X12K
energy=3.28 KJ
=3.3 X10^2?

how do you solve for b. I don't know how to do it. Is this working correct?
 
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For (a), please check your delta t.

For (b), you use the same equation you did for (a). You solve for c, the specific heat capacity. The idea is to find this value and look it up in a table and see what material it corresponds to.
 

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