1. Hydrogen peroxide is stored in a dark, opaque container because, at room temperature, it spontaneously forms water and oxygen in the presence of light. Even if exposure to light is minimal, hydrogen peroxide will break down over time, giving it a limited shelf life. a. What can you infer about the relative thermodynamic and kinetic stability of hydrogen peroxide?

b. What role does light play in the decomposition of hydrogen peroxide?

c. If manganese dioxide is added to hydrogen peroxide, bubbles of gas are produced immediately, but the MnO2 is not changed in the reaction. What can you conclude about the role of manganese dioxide and its effect on the activation energy in the decomposition reaction?

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.

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.