Confirmation that I set this correctly and answer are much appreciated! 6. Calcu
ID: 481455 • Letter: C
Question
Confirmation that I set this correctly and answer are much appreciated! 6. Calculate the amount of heat (in kl) required to convert 44.0 g of solid ethanol (molar mass 46.1 g/mol) at -126.0 oC to gaseous ethanol at 94 oC. (specific heat capacities: solid: 2.42 Jg.oC, liquid: point: -114 oC, boiling point: 78 oC). Show all math steps (including temperature changes) and include units in the methods and answers. For each step, specify what you are solving for (heating liquid, melting solid etc.). Mass of ethane 44 Moves of eamanal 40. alm Hest red males x heat f fusion mass x specific heat x temp chante a metes x heat of vaporization mass x Spec heat x temperature change gas 78)
Explanation / Answer
Q = m c T
Q = quantity of heat in joules (J)
m = mass of the substance acting as the environment in
grams (g)
c = specific heat capacity (4.19 for H2O) in J/(g oC)
T = change in temperature = Tfinal - Tinitial in oC
1) The Ethanol does five things:
a) heat up from -126 to -114 Deg cel
b) melt at -114 Deg cel
c) heat up from -114 to 78 Deg cel
d) converts to vapour at 78 Deg cel
e) heat up from 78 to 94 Deg cel
2) The five calculations are:
Qa = 44 x (126-114) x 2.42 = 1277.76 Joules
Qb = 44 x 4.9 x 103 / 46.06 = 4680.85 Joules
Qc = 44 x 92 x 2.44 = 9877.12 Joules
Qd = 44 x 38.6 x 103 / 46.06 = 36873.64 Joules
Qe = 44 x (94-78) x 1.7 = 1196.8 JOules
Total heat = Qa + Qb + Qc + Qd + Qe
Total heat needed = 53906.17 Joules ot 53.91 Kilo Joules
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