The activation energy for the diffusion of copper in silver is 193,000 J/mol. Calculate the diffusion coefficient at 1200 K (927C), given that D at 1000 K (727C) is 1.0 x10^-14 m2 /s.

A thermal evaporator is used to deposit aluminum. The aluminum charge is maintained at a uniform temperature of 1100 o C. If the the vapor pressure of aluminum is about 1x10-3 torr at that temperature, calculate the evaporation rate of aluminum?

A sample of lead has a mass of 31.00 kg and a density of 1.130 x104 kg/m3 at 0°C. (Assume the average linear expansion coefficient for lead is  2.900 x10-5(°C−1).) What is the density of lead at 95.00°C? (Give your answer to four significant figures.)

You wish to carburize 0.2 wt% C steel ball bearings. The balls have a diameter of 2.5 mm. You anneal them at 930 °C in an atmosphere which fixes the surface carbon concentration at 1 wt% C. (a) How long will it take to raise the average C concentration to 0.6 wt% ? (b) What is the concentration at the centre of each ball at this time?