Funny Harry Potter meme

Study the following reaction carefully. what classification should this reaction have? 4al + 3o2 2al2o3synthesisdecompositionsingle replacementdouble displacement

Carbon is allowed to diffuse through a steel plate 15 mm thick. the concentrations of carbon at the two faces are 0.65 and 0.30 kg c/m^3 fe, which are maintained constant. if the preexponential and activation energy are 6.2 x 10-7 m2 /s and 80,000 j/mol, respectively, compute the temperature at which the diffusion flux is 1.43 x 10^-9 kg/m^2 -s.

Which of the following forces require physical contact? tension air resistance friction magnetic force applied force