How is the atomic mass of an element related to a mole? O A. The atomic mass, in grams, is the mass of 6.02 x 1023 electrons.
B. The atomic mass, in grams, is the mass of one mole of protons.
C. The atomic mass, in grams, is the mass of 6.02 x 1023 moles.
O D. The atomic mass, in grams, is the mass of one mole of atoms.

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.

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.