PLEASE HELP An aluminum pop can contains 2.85 x 10^23 atoms and has an average height of 12.3 cm. Assume the distance between the Sun and the Earth is 149.6 million km.

a) Calculate the mass of the can

b) If mole of aluminum pop cans, stacked on top of one another, how many times would it reach from here ( on Earth ) to the sun and back?

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.

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.