Question

When boiling water, a hot plate takes an average of 7 minutes (min) and 16 seconds [s] to boil 150 milliliters [ml] of water. Assume the temperature in the lab is 78 degrees Fahrenheit (°F). The hot plate is rated to provide 379 watts [W]. If we wish to boil 150 milliliters (ml) of acetone using this same hot plate, how long do we expect the process to take? Acetone has a boiling point of 56 degrees Celsius [°C]. [Hint: you must determine the efficiency of the hotplate.1 Density of water Material Temperature Change 1 K = 1°C = 1.8 °F = 1.8 PR T[OF] -32 T[°C] -0 180 100 T[K] = T[°C] +273 T['R] = T[OF] + 460 Water Aluminum Copper Lead Air Helium Acetone Specific heat 4.184 0.897 0.385 0.127 1.012 5.1932 2.15 Liquids Acetone Benzene Citric Acid Gasoline Glycerin lodine Mercury Mineral oil Olive oil Propane Sea water Toluene Water SG 0.785 0.875 1.67 0.739 1.26 4.93 13.6 0.900 0.703 0.806 1.03 0.865 1.00 -1.94 Time 1 d = 24 h 1 h = 60 min 1 min = 60 s 1 yr = 365 d Mass 1 kg = 2.205 lbm 1 slug = 14.5939 kg 1 slug = 32.2 lbm Length 1 m = 3.28 ft 1 km = 0.621 mi 1 in = 2.54 cm 1 mi = 5,280 ft 1 yd = 3 ft Volume 1L = 0.264 gal 1L = 0.0353 ft? 1L = 33.8 fl oz 1 mL = 1 cm3 Energy 1 J = 0.239 cal = 9.48 x 10-4 BTU = 0.7376 ft lb- 1 kWh = 3,600,000 J

Answer 1

Here first we have to find efficiency cy of hot plope (heating element) na Heaf required to boil water x 100 % Heap supplied by hot plate ! heat required to boil water - mx SXAT here m- mass of water - Molume NV) x density cd of wales/ d - 150cm3 x 1x11 - 150g [:d= SG * ! cm3 [1ma-lom S-specific heat of wales - 4.184 - DT - change in temperature - 100°c - 78°F - 100 °C - 478 -32) X C [ t(o)- (Toy) = 10 °C - 46X = 7414 you | by 7 + power of hot plate = p = 379 w - 379 I time towen to boil motes - t = 7 min 165 = 7860+165 :t 4365 Now, - MXSAT vi pxt X100 % mn (150g * 4.1895* * 74.446) 5 x 100 % I x 4365) J as n 28+27h Now, mass of Acefon - MA = vxd = 150 cm x 0.785419 :. MA= 117.75g specific heap of Acetone = SA= 2.15 I - JK change in temperature of Acefone ATA = 56°C-78°F .:STA = 56°c- (78-32x50C = 30.44°C = 30.44K

. heat required to boil the Acetone = MAXSAY AT - 11+1 Sax 21s 2 х 30 «чук - 1706-211 Let time taken to boid the Acetone by hot plate is t. Now, we can write Рx texn - MAY (дXATA on, ta - mn Y (дя БТА Рx7 - 1706-24 - 17 06:24x/ зтоту 29. 2+ - 239x 28.71 of t : : 192 х 12 S tA= min 125 | wh 12 г