When 3.93 grams of lactic acid, CHoOs(s), are burned in a bomb
calorimeter that has a total heat capacity of 10.80 kJ-K-1, the
temperature of the calorimeter increases by 5.43 K. Assume AHrxn
=
AErxn. Given that AH°f of H¿O(I) = -285.8 kJ-mol-1 and AH°f of CO:(g)
= -393.5 kJ• mol-1, calculate the AH°f of lactic acid.
Answers
The heat released in the combustion of lactic acid is absorbed by the
calorimeter and in the decomposition of the lactic acid.
ΔH°f of lactic acid is approximately -716.2 kJ
Reasons:
Known parameters are;
Mass of the lactic acid = 3.93 grams
Heat capacity of the bomb calorimeter = 10.80 kJ·K⁻¹
Change in temperature of the calorimeter, ΔT = 5.34 K
ΔHrxn = ΔErxn
ΔH°f of H₂O(l) = -285.8 kJ·mol⁻¹
ΔH°f of CO₂(g) = -393.5 kJ·mol⁻¹
The chemical equation for the reaction is presented as follows;
C₃H₆O₃ + 2O₂ → 3CO₂ + 3H₂OThe heat of the reaction = 10.80 kJ·K⁻¹ × 5.34 K = 57.672 kJ
Molar mass of C₃H₆O₃ = 90.07 g/mol
Number of moles of C₃H₆O₃ = [tex]\dfrac{3.93 \, g}{90.07 \, g/mol}[/tex] = 0.043633 moles
Number of moles of CO₂ produced = 3 × 0.043633 moles = 0.130899 moles
Heat produced = 0.130899 mole × -285.8 kJ·mol⁻¹ = -37.4109342 kJ
Moles of H₂O produced = 0.130899 moles
Heat produced = 0.130899 mole × -393.5 ≈ -51.51 kJ
Therefore, we have;
Heat absorbed by the lactic acid = ΔH°f of H₂O + ΔH°f of CO₂ + Heat absorbed by the calorimeter
Which gives;
Heat absorbed by lactic acid = -37.4109342 kJ - 51.51 kJ + 57.672 kJ ≈ -31.249 kJ
The heat absorbed by the lactic acid ≈ -31.249 kJ
[tex]\Delta H^{\circ}f \ of \ C_3H_6O_3 = \dfrac{-31.249}{0.043633} \approx -716.2[/tex]
ΔH°f of C₃H₆O₃ ≈ -716.2 kJ
Heat of formation of lactic acid ≈ -716.2 kJ.
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Answers
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You and your family have just arrived in Water Cycle Land. You are going on a new ride called the Water Cycle. You sit in your seat and the ride begins. All of a sudden something goes wrong. Your body is turning into a water droplet! Think about what you have learned about the water cycle. Now tell a story about what happens to you as you travel through the water cycle. By the way, how do you get your body back to normal?
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Answer:
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Answers
Answer:
5.9405*10^14 Hz
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djxgfchkgvjhbkjlnk:Hg/ufy
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fzdxgfchg,jv.hkbjnj.jhcgbc
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Answer:
the drops of liquid are coming from the decreases. they are formed as the motion of the water particles in the air gas. this change in motion cause air in the air to change from a liquid to a water
Hello there!
The drops of liquid are coming from the air. They are formed as the motion of particles in the air decreases. This change in motion causes water in the air to change from a liquid to a gas.
Hope this helps you!
~Just a joyful teen
[tex]SilentNature :)[/tex]
✿❀❁❀✿Scientific Notation!!!!!
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Explanation:
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= 0.376×10^-7.
b) (4.36×10⁸×1.82×10³)/(0.0856×4.7×10⁶)
= (7.9352×10⁸+³)/(0.40232×10⁶)
= 19.72×10⁸+³-⁶ = 19.72×10⁵
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Answers
Answer
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because why not