The melting of ice at body temperature is an endothermic process:H2O(s) _>H2O(1) ΔΗ= +6.0kJ/mo.Thus eating ice counteracts the exothermic processes of metabolizing food. How much ice (in grams) would you have to eat to counteract the energy gained by eating 28.3g of peanuts (13 kJ/g)?
Correct answer: D. 1100 g
- A. 78 g
- B. 110 g
- C. 370 g
- D. 1100 g
Explanation
Now, the molar mass of water (H2O) is approximately 18.015 g/mol.The mass of ice (in grams) required to absorb this energy is:mass of ice = moles of ice x molar mass of watermass of ice = 61.48 mol x 18.015 g/molmass of ice = 1107.66 gSo, the correct answer is:d. 1100 gTherefore, you would need to eat 1100 grams of ice to counteract the energy gained by eating 28.3 grams of peanuts.
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About Thermochemistry and Energetics of Chemical Reactions
Thermochemistry measures energy changes in chemical reactions and distinguishes exothermic from endothermic processes. Work covers systems, surroundings and state functions, internal energy, the first law of thermodynamics, enthalpy and Hess's law, including the sign conventions used when heat enters or leaves a system.
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