Calculate the mass of iron needed to produce 971 kJ of heat according to the following equation.
4 Fe + 302 → 2 Fe2O3 + 1120 kJ

b) nuclear ive learned that in a pedtrodic table

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.

answer: gold foil experiment - he shot alpha particles at a gold foil

explanation: