For the decomposition of urea in the reaction: CO(NH2)2(aq) + 2 H2O(l) → 2NH4 + (aq) + CO3 2− (aq) the pseudo first-order rate constant is 1.2 × 10−7 s −1 at 60°C and 4.6 × 10 −7 s −1 at 70°C. A) Estimate the activation energy b) Calculate the entropy of activation of the reaction and comment on the value.

Sound is a disturbance that travels through a medium as a

Asolid round steel rod 6.25 mm in diameter and 375 mm long is rigidly bonded to the end of solid square brass rod 25 mm on a side and 300 mm long. the geometric axes of the bare are along the same line. an axial tensile force of 5.4 kn is applied at the extreme ends of the assembly. for steel e = 200 gpa and for brass e = 90 gpa. determine the total elongation for the assembly.

Athin nonconducting rod with a uniform distribution of positive charge q is bent into a circle of radius r. the central perpendicular axis through the ring is a z-axis, with the origin at the center of the ring. a) what is the magnitude of the electric field due to the rod at z = 0? n/c (b) what is the magnitude of the electric field due to the rod at z = infinity? n/c (c) in terms of r, at what positive value of z is that magnitude maximum? r (d) if r = 4.00 cm and q = 9.00 µc, what is the maximum magnitude? n/c