It takes 6.86 kg of ethylene glycol (antifreeze; molar mass = 62.07 g/mol) to decrease the freezing point of 6.50 kg of water to -25 oF (-31.7 oC). How much sucrose (C12H22O11) would it take to decrease the freezing point of 6.50 kg of water to -25?

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.