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A 217 g metal absorbs 1.43 kJ and warms from 24.5 degrees C to 39.1 degrees C. What is its specific heat and likely identity?
A0.451 J/g degree C, likely gold
B0.451 J/g degree C, likely iron
C0.897 J/g degree C, likely iron
D0.130 J/g degree C, likely lead
Answer & Solution
Correct answer: B. 0.451 J/g degree C, likely iron
1. Convert the heat: 1.43 kJ is 1430 J.
2. The temperature change is 39.1 minus 24.5, which is 14.6 degrees Celsius.
3. The denominator is 217 g times 14.6 degrees Celsius, that is 3168.2 gram degrees Celsius.
4. Divide: 1430 divided by 3168.2 gives 0.4514 J per gram per degree Celsius.
5. Rounded, the specific heat is 0.451 J/g degree C.
6. The tabulated value for iron is 0.449 J/g degree C, which is the closest match.
7. Gold is 0.129 and lead is 0.130 J/g degree C, both far too small to fit this result.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 5 "Thermochemistry", section 5.1 Energy Basics_
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