Question

How long would it take to heat a 3 m cubic room by 10*C, using 360,000 J of work, with a 1,000 W space heater?

Answer 1

Explanation:

Hot things have more energy than their coldHeat is really just kinetic energyon microscopic scales: the vibration or otherwise fast motion of individual atoms/moleculesHeat is frequently quantified by calories (or Btu)One calorie (4.184 J) raises one gram of H2O 1ºCOne Calorie (4184 J) raises one kilogram of H2O 1ºCOne Btu (1055 J) raises one pound of H2O 1ºF24

Different materials have different capacitiesfor heatAdd the same energy to different materials, and you’ll get different temperature risesQuantified as heat capacityWater is exceptional, with 4,184 J/kg/ºCMost materials are about 1,000 J/kg/ºC (including wood, air, metals)Q = mcΔTQ = heat energy , JM = mass, kg,C = specific heat capacity (J/kg/ºC)ΔT = change in temperature (oC)Example: to add 10ºC to a room 3 meters on a side (cubic), how much energy do we need?air density is 1.3 kg/m3, and we have 27 m3, so 35 kg of air; and we need 1000 J per kg per ºC, so we end up needing 350,000 J (= 83.6 Cal)25

CHEMICALENERGYElectrostatic energy (associated with charged particles, like electrons) is stored in the chemical bonds of substances. Rearranging these bonds can release energy (some reactions requireenergy to be put in)26