Carol E. answered • 07/17/14
Tutor
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(718)
Chemistry is my specialty!!
Harley,
See the answers to your other questions and
Remember the equation
ΔH = -Ccal x ΔT.
Hints:
1) make sure ΔT in in K
2) 1 nutritional calorie = 4.2 kJ
3) give the answer on a per gram basis of candy
I think you can take it from here!!
Carol E.
Do you want to share your work so far? I may be able to help if I see what you've tried.
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07/21/14
Harley W.
I multiplied 46.80 x 2.36 then took that answer and converted calories. And finally divided it by 3.40.
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07/21/14
Carol E.
Harley, Here's what I get
ΔH = -Ccal x ΔT
- 46.80 kJ/K x 2.36 K = -110.448 kJ
convert to nutritional calories
-110.48 kJ (1 Calorie/4.2 kJ) = -26.3 Calorie
Calories per gram
-26.3 C/ 3.40 g = -7.73 Calorie/gram
Did you get something different?
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07/21/14
Steven R.
working on a similiar problem.... only question I have is the Calorie being negative... I get that the Ccal was -... but trying to understand the negative behind a calorie....
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10/26/15
Carol E.
Steven,
When reporting food Calories, the negative sign is omitted. In thermochemistry the negative sign indicates that the reaction is exothermic meaning energy is released. Since we obviously eat food in order to get energy from it, the negative sign isn't meaningful.
Also note that a food Calorie (with a capital C) equals 1000 thermochemical calories.
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10/27/15
Harley W.
07/21/14