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einsteindude einsteindude
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Posts: 5058
7 years ago
A 2.50 g sample of french fries is placed in a calorimeter with 500.0 g of water at an initial temperature of 21.0 °C. After combustion of the french fries the water has a temperature of 48.0 °C. What is the heat content in kJ/g of the french fries?
A) 70.9 kJ
B) 2.63 kJ
C) 282 kJ
D) 22 600 kJ
E) 22.6 kJ
Textbook 

Conceptual Physical Science


Edition: 6th
Authors:
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f_zah1f_zah1
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7 years ago
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E

---

A calorie (1 cal) is the amount of energy needed to raise 1 g of water by 1 degree Celsius.
So 2.5 g of french fries raised 500 g of water by 27 degrees Celsius, or 13,500 cal.
Convert cal to kJ
13500 cal* 1 Cal/1000 cal = 13.5 Cal* 4.184 kJ/1 Cal = 56.484 kJ
So 2.5g french fries produced 56.484 kJ
56.484/2.5 = 22.59 g/kJ or 23 g/kJ

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